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Gillespie NA, Bell TR, Hearn GC, Hess JL, Tsuang MT, Lyons MJ, Franz CE, Kremen WS, Glatt SJ. A twin analysis to estimate genetic and environmental factors contributing to variation in weighted gene co-expression network module eigengenes. Am J Med Genet B Neuropsychiatr Genet 2024:e33003. [PMID: 39126209 DOI: 10.1002/ajmg.b.33003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 06/18/2024] [Accepted: 07/22/2024] [Indexed: 08/12/2024]
Abstract
Multivariate network-based analytic methods such as weighted gene co-expression network analysis are frequently applied to human and animal gene-expression data to estimate the first principal component of a module, or module eigengene (ME). MEs are interpreted as multivariate summaries of correlated gene-expression patterns and network connectivity across genes within a module. As such, they have the potential to elucidate the mechanisms by which molecular genomic variation contributes to individual differences in complex traits. Although increasingly used to test for associations between modules and complex traits, the genetic and environmental etiology of MEs has not been empirically established. It is unclear if, and to what degree, individual differences in blood-derived MEs reflect random variation versus familial aggregation arising from heritable or shared environmental influences. We used biometrical genetic analyses to estimate the contribution of genetic and environmental influences on MEs derived from blood lymphocytes collected on a sample of N = 661 older male twins from the Vietnam Era Twin Study of Aging (VETSA) whose mean age at assessment was 67.7 years (SD = 2.6 years, range = 62-74 years). Of the 26 detected MEs, 14 (56%) had statistically significant additive genetic variation with an average heritability of 44% (SD = 0.08, range = 35%-64%). Despite the relatively small sample size, this demonstration of significant family aggregation including estimates of heritability in 14 of the 26 MEs suggests that blood-based MEs are reliable and merit further exploration in terms of their associations with complex traits and diseases.
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Affiliation(s)
- Nathan A Gillespie
- Virginia Institute for Psychiatric and Behavior Genetics, Virginia Commonwealth University, Virginia, USA
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Tyler R Bell
- Department of Psychiatry, University of California San Diego, La Jolla, California, USA
- Center for Behavior Genetics of Aging, University of California San Diego, La Jolla, California, USA
| | - Gentry C Hearn
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
| | - Jonathan L Hess
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
| | - Ming T Tsuang
- Department of Psychiatry, University of California San Diego, La Jolla, California, USA
| | - Michael J Lyons
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
| | - Carol E Franz
- Department of Psychiatry, University of California San Diego, La Jolla, California, USA
- Center for Behavior Genetics of Aging, University of California San Diego, La Jolla, California, USA
| | - William S Kremen
- Department of Psychiatry, University of California San Diego, La Jolla, California, USA
- Center for Behavior Genetics of Aging, University of California San Diego, La Jolla, California, USA
| | - Stephen J Glatt
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, New York, USA
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2
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Wilderman A, D'haene E, Baetens M, Yankee TN, Winchester EW, Glidden N, Roets E, Van Dorpe J, Janssens S, Miller DE, Galey M, Brown KM, Stottmann RW, Vergult S, Weaver KN, Brugmann SA, Cox TC, Cotney J. A distant global control region is essential for normal expression of anterior HOXA genes during mouse and human craniofacial development. Nat Commun 2024; 15:136. [PMID: 38167838 PMCID: PMC10762089 DOI: 10.1038/s41467-023-44506-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 12/14/2023] [Indexed: 01/05/2024] Open
Abstract
Craniofacial abnormalities account for approximately one third of birth defects. The regulatory programs that build the face require precisely controlled spatiotemporal gene expression, achieved through tissue-specific enhancers. Clusters of coactivated enhancers and their target genes, known as superenhancers, are important in determining cell identity but have been largely unexplored in development. In this study we identified superenhancer regions unique to human embryonic craniofacial tissue. To demonstrate the importance of such regions in craniofacial development and disease, we focused on an ~600 kb noncoding region located between NPVF and NFE2L3. We identified long range interactions with this region in both human and mouse embryonic craniofacial tissue with the anterior portion of the HOXA gene cluster. Mice lacking this superenhancer exhibit perinatal lethality, and present with highly penetrant skull defects and orofacial clefts phenocopying Hoxa2-/- mice. Moreover, we identified two cases of de novo copy number changes of the superenhancer in humans both with severe craniofacial abnormalities. This evidence suggests we have identified a critical noncoding locus control region that specifically regulates anterior HOXA genes and copy number changes are pathogenic in human patients.
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Affiliation(s)
| | - Eva D'haene
- Center for Medical Genetics, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Machteld Baetens
- Center for Medical Genetics, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | | | - Emma Wentworth Winchester
- Graduate Program UConn Health, Farmington, CT, USA
- University of Connecticut School of Dental Medicine, Farmington, CT, USA
| | - Nicole Glidden
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Ellen Roets
- Department of Obstetrics, Women's Clinic, Ghent University Hospital, Ghent, Belgium
| | - Jo Van Dorpe
- Department of Pathology, Ghent University, Ghent University Hospital, Ghent, Belgium
| | - Sandra Janssens
- Center for Medical Genetics, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Danny E Miller
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Washington, WA, USA
- Seattle Children's Hospital, Seattle, WA, 98195, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
- Brotman Baty Institute of Precision Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Miranda Galey
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Washington, WA, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Kari M Brown
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Rolf W Stottmann
- Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, USA
- The Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University School of Medicine, Columbus, OH, USA
| | - Sarah Vergult
- Center for Medical Genetics, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - K Nicole Weaver
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Samantha A Brugmann
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Timothy C Cox
- Department of Oral & Craniofacial Sciences, University of Missouri Kansas City, Kansas City, MO, USA
- Department of Pediatrics, University of Missouri Kansas City, Kansas City, MO, USA
| | - Justin Cotney
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT, USA.
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA.
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3
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Rajderkar S, Barozzi I, Zhu Y, Hu R, Zhang Y, Li B, Alcaina Caro A, Fukuda-Yuzawa Y, Kelman G, Akeza A, Blow MJ, Pham Q, Harrington AN, Godoy J, Meky EM, von Maydell K, Hunter RD, Akiyama JA, Novak CS, Plajzer-Frick I, Afzal V, Tran S, Lopez-Rios J, Talkowski ME, Lloyd KCK, Ren B, Dickel DE, Visel A, Pennacchio LA. Topologically associating domain boundaries are required for normal genome function. Commun Biol 2023; 6:435. [PMID: 37081156 PMCID: PMC10119121 DOI: 10.1038/s42003-023-04819-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 04/06/2023] [Indexed: 04/22/2023] Open
Abstract
Topologically associating domain (TAD) boundaries partition the genome into distinct regulatory territories. Anecdotal evidence suggests that their disruption may interfere with normal gene expression and cause disease phenotypes1-3, but the overall extent to which this occurs remains unknown. Here we demonstrate that targeted deletions of TAD boundaries cause a range of disruptions to normal in vivo genome function and organismal development. We used CRISPR genome editing in mice to individually delete eight TAD boundaries (11-80 kb in size) from the genome. All deletions examined resulted in detectable molecular or organismal phenotypes, which included altered chromatin interactions or gene expression, reduced viability, and anatomical phenotypes. We observed changes in local 3D chromatin architecture in 7 of 8 (88%) cases, including the merging of TADs and altered contact frequencies within TADs adjacent to the deleted boundary. For 5 of 8 (63%) loci examined, boundary deletions were associated with increased embryonic lethality or other developmental phenotypes. For example, a TAD boundary deletion near Smad3/Smad6 caused complete embryonic lethality, while a deletion near Tbx5/Lhx5 resulted in a severe lung malformation. Our findings demonstrate the importance of TAD boundary sequences for in vivo genome function and reinforce the critical need to carefully consider the potential pathogenicity of noncoding deletions affecting TAD boundaries in clinical genetics screening.
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Affiliation(s)
- Sudha Rajderkar
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Iros Barozzi
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, 1090, Vienna, Austria
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Yiwen Zhu
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Rong Hu
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Yanxiao Zhang
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Bin Li
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Ana Alcaina Caro
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide Junta de Andalucía, 41013, Seville, Spain
| | - Yoko Fukuda-Yuzawa
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
- Institute of Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Guy Kelman
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
- The Jerusalem Center for Personalized Computational Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Adyam Akeza
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Matthew J Blow
- U.S. Department of Energy Joint Genome Institute, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Quan Pham
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Anne N Harrington
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Janeth Godoy
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Eman M Meky
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Kianna von Maydell
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Riana D Hunter
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Jennifer A Akiyama
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Catherine S Novak
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Ingrid Plajzer-Frick
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Veena Afzal
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Stella Tran
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Javier Lopez-Rios
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide Junta de Andalucía, 41013, Seville, Spain
| | - Michael E Talkowski
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, 02114, USA
- Program in Medical and Population Genetics and Stanley Center for Psychiatric Disorders, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA, 02142, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - K C Kent Lloyd
- Mouse Biology Program, University of California, Davis, Davis, CA, USA
- Department of Surgery, School of Medicine, University of California, Davis, Davis, CA, USA
| | - Bing Ren
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
- Center for Epigenomics, University of California, San Diego School of Medicine, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, CA, USA
- Institute of Genome Medicine, Moores Cancer Center, University of California, San Diego School of Medicine, La Jolla, CA, USA
| | - Diane E Dickel
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Axel Visel
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA.
- U.S. Department of Energy Joint Genome Institute, 1 Cyclotron Road, Berkeley, CA, 94720, USA.
- School of Natural Sciences, University of California, Merced, Merced, CA, USA.
| | - Len A Pennacchio
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA.
- U.S. Department of Energy Joint Genome Institute, 1 Cyclotron Road, Berkeley, CA, 94720, USA.
- Comparative Biochemistry Program, University of California, Berkeley, CA, 94720, USA.
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4
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Zeng L, Liu Y, Yu ZG, Liu Y. iEnhancer-DLRA: identification of enhancers and their strengths by a self-attention fusion strategy for local and global features. Brief Funct Genomics 2022; 21:399-407. [PMID: 35942693 DOI: 10.1093/bfgp/elac023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 06/30/2022] [Accepted: 07/12/2022] [Indexed: 11/14/2022] Open
Abstract
Identification and classification of enhancers are highly significant because they play crucial roles in controlling gene transcription. Recently, several deep learning-based methods for identifying enhancers and their strengths have been developed. However, existing methods are usually limited because they use only local or only global features. The combination of local and global features is critical to further improve the prediction performance. In this work, we propose a novel deep learning-based method, called iEnhancer-DLRA, to identify enhancers and their strengths. iEnhancer-DLRA extracts local and multi-scale global features of sequences by using a residual convolutional network and two bidirectional long short-term memory networks. Then, a self-attention fusion strategy is proposed to deeply integrate these local and global features. The experimental results on the independent test dataset indicate that iEnhancer-DLRA performs better than nine existing state-of-the-art methods in both identification and classification of enhancers in almost all metrics. iEnhancer-DLRA achieves 13.8% (for identifying enhancers) and 12.6% (for classifying strengths) improvement in accuracy compared with the best existing state-of-the-art method. This is the first time that the accuracy of an enhancer identifier exceeds 0.9 and the accuracy of the enhancer classifier exceeds 0.8 on the independent test set. Moreover, iEnhancer-DLRA achieves superior predictive performance on the rice dataset compared with the state-of-the-art method RiceENN.
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Affiliation(s)
- Li Zeng
- Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education, Xiangtan University, 411105, Xiangtan, China
| | - Yang Liu
- Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education, Xiangtan University, 411105, Xiangtan, China
| | - Zu-Guo Yu
- Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education, Xiangtan University, 411105, Xiangtan, China
| | - Yuansheng Liu
- College of Computer Science and Electronic Engineering, Hunan University, 2 Lushan S Rd, Yuelu District, 410086, Changsha, China
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5
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Lee DI, Roy S. GRiNCH: simultaneous smoothing and detection of topological units of genome organization from sparse chromatin contact count matrices with matrix factorization. Genome Biol 2021; 22:164. [PMID: 34034791 PMCID: PMC8152090 DOI: 10.1186/s13059-021-02378-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 05/10/2021] [Indexed: 11/18/2022] Open
Abstract
High-throughput chromosome conformation capture assays, such as Hi-C, have shown that the genome is organized into organizational units such as topologically associating domains (TADs), which can impact gene regulatory processes. The sparsity of Hi-C matrices poses a challenge for reliable detection of these units. We present GRiNCH, a constrained matrix-factorization-based approach for simultaneous smoothing and discovery of TADs from sparse contact count matrices. GRiNCH shows superior performance against seven TAD-calling methods and three smoothing methods. GRiNCH is applicable to multiple platforms including SPRITE and HiChIP and can predict novel boundary factors with potential roles in genome organization.
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Affiliation(s)
- Da-Inn Lee
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, 53715, USA
| | - Sushmita Roy
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, 53715, USA. .,Wisconsin Institute for Discovery, 330 N. Orchard Street, Madison, 53715, USA.
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6
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Niu K, Luo X, Zhang S, Teng Z, Zhang T, Zhao Y. iEnhancer-EBLSTM: Identifying Enhancers and Strengths by Ensembles of Bidirectional Long Short-Term Memory. Front Genet 2021; 12:665498. [PMID: 33833783 PMCID: PMC8021722 DOI: 10.3389/fgene.2021.665498] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/01/2021] [Indexed: 12/26/2022] Open
Abstract
Enhancers are regulatory DNA sequences that could be bound by specific proteins named transcription factors (TFs). The interactions between enhancers and TFs regulate specific genes by increasing the target gene expression. Therefore, enhancer identification and classification have been a critical issue in the enhancer field. Unfortunately, so far there has been a lack of suitable methods to identify enhancers. Previous research has mainly focused on the features of the enhancer's function and interactions, which ignores the sequence information. As we know, the recurrent neural network (RNN) and long short-term memory (LSTM) models are currently the most common methods for processing time series data. LSTM is more suitable than RNN to address the DNA sequence. In this paper, we take the advantages of LSTM to build a method named iEnhancer-EBLSTM to identify enhancers. iEnhancer-ensembles of bidirectional LSTM (EBLSTM) consists of two steps. In the first step, we extract subsequences by sliding a 3-mer window along the DNA sequence as features. Second, EBLSTM model is used to identify enhancers from the candidate input sequences. We use the dataset from the study of Quang H et al. as the benchmarks. The experimental results from the datasets demonstrate the efficiency of our proposed model.
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Affiliation(s)
- Kun Niu
- College of Information and Computer Engineering, Northeast Forestry University, Harbin, China
| | - Ximei Luo
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Shumei Zhang
- College of Information and Computer Engineering, Northeast Forestry University, Harbin, China
| | - Zhixia Teng
- College of Information and Computer Engineering, Northeast Forestry University, Harbin, China
| | - Tianjiao Zhang
- College of Information and Computer Engineering, Northeast Forestry University, Harbin, China
| | - Yuming Zhao
- College of Information and Computer Engineering, Northeast Forestry University, Harbin, China
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7
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Sethi S, Vorontsov IE, Kulakovskiy IV, Greenaway S, Williams J, Makeev VJ, Brown SDM, Simon MM, Mallon AM. A holistic view of mouse enhancer architectures reveals analogous pleiotropic effects and correlation with human disease. BMC Genomics 2020; 21:754. [PMID: 33138777 PMCID: PMC7607678 DOI: 10.1186/s12864-020-07109-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 09/29/2020] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Efforts to elucidate the function of enhancers in vivo are underway but their vast numbers alongside differing enhancer architectures make it difficult to determine their impact on gene activity. By systematically annotating multiple mouse tissues with super- and typical-enhancers, we have explored their relationship with gene function and phenotype. RESULTS Though super-enhancers drive high total- and tissue-specific expression of their associated genes, we find that typical-enhancers also contribute heavily to the tissue-specific expression landscape on account of their large numbers in the genome. Unexpectedly, we demonstrate that both enhancer types are preferentially associated with relevant 'tissue-type' phenotypes and exhibit no difference in phenotype effect size or pleiotropy. Modelling regulatory data alongside molecular data, we built a predictive model to infer gene-phenotype associations and use this model to predict potentially novel disease-associated genes. CONCLUSION Overall our findings reveal that differing enhancer architectures have a similar impact on mammalian phenotypes whilst harbouring differing cellular and expression effects. Together, our results systematically characterise enhancers with predicted phenotypic traits endorsing the role for both types of enhancers in human disease and disorders.
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Affiliation(s)
- Siddharth Sethi
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, OX11 0RD, UK
| | - Ilya E Vorontsov
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina 3, Moscow, 119991, Russia
- Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, Pushchino, Moscow Region, 142290, Russia
| | - Ivan V Kulakovskiy
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina 3, Moscow, 119991, Russia
- Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, Pushchino, Moscow Region, 142290, Russia
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilova 32, Moscow, 119991, Russia
| | - Simon Greenaway
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, OX11 0RD, UK
| | - John Williams
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, OX11 0RD, UK
- Institute of Translational Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, B15 2TH, UK
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Vsevolod J Makeev
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina 3, Moscow, 119991, Russia
- Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, Pushchino, Moscow Region, 142290, Russia
- Moscow Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudny, Moscow Region, 141700, Russia
| | - Steve D M Brown
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, OX11 0RD, UK
| | - Michelle M Simon
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, OX11 0RD, UK.
| | - Ann-Marie Mallon
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, OX11 0RD, UK.
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8
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Sadler B, Haller G, Antunes L, Nikolov M, Amarillo I, Coe B, Dobbs MB, Gurnett CA. Rare and de novo duplications containing SHOX in clubfoot. J Med Genet 2020; 57:851-857. [PMID: 32518174 PMCID: PMC7688552 DOI: 10.1136/jmedgenet-2020-106842] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 11/12/2022]
Abstract
Introduction Congenital clubfoot is a common birth defect that affects at least 0.1% of all births. Nearly 25% cases are familial and the remaining are sporadic in inheritance. Copy number variants (CNVs) involving transcriptional regulators of limb development, including PITX1 and TBX4, have previously been shown to cause familial clubfoot, but much of the heritability remains unexplained. Methods Exome sequence data from 816 unrelated clubfoot cases and 2645 in-house controls were analysed using coverage data to identify rare CNVs. The precise size and location of duplications were then determined using high-density Affymetrix Cytoscan chromosomal microarray (CMA). Segregation in families and de novo status were determined using qantitative PCR. Results Chromosome Xp22.33 duplications involving SHOX were identified in 1.1% of cases (9/816) compared with 0.07% of in-house controls (2/2645) (p=7.98×10−5, OR=14.57) and 0.27% (38/13592) of Atherosclerosis Risk in Communities/the Wellcome Trust Case Control Consortium 2 controls (p=0.001, OR=3.97). CMA validation confirmed an overlapping 180.28 kb duplicated region that included SHOX exons as well as downstream non-coding regions. In four of six sporadic cases where DNA was available for unaffected parents, the duplication was de novo. The probability of four de novo mutations in SHOX by chance in a cohort of 450 sporadic clubfoot cases is 5.4×10–10. Conclusions Microduplications of the pseudoautosomal chromosome Xp22.33 region (PAR1) containing SHOX and downstream enhancer elements occur in ~1% of patients with clubfoot. SHOX and regulatory regions have previously been implicated in skeletal dysplasia as well as idiopathic short stature, but have not yet been reported in clubfoot. SHOX duplications likely contribute to clubfoot pathogenesis by altering early limb development.
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Affiliation(s)
- Brooke Sadler
- Department of Neurology, Washington University in Saint Louis School of Medicine, Saint Louis, Missouri, USA
| | - Gabe Haller
- Department of Orthopedic Surgery, Washington University in Saint Louis School of Medicine, Saint Louis, Missouri, USA
| | - Lilian Antunes
- Department of Neurology, Washington University in Saint Louis School of Medicine, Saint Louis, Missouri, USA
| | - Momchil Nikolov
- Department of Neurology, Washington University in Saint Louis School of Medicine, Saint Louis, Missouri, USA
| | - Ina Amarillo
- Department of Pathology and Immunology, Washington University in Saint Louis School of Medicine, Saint Louis, Missouri, USA
| | - Bradley Coe
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington, USA.,Department of Pathology & Laboratory Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Matthew B Dobbs
- Department of Orthopedic Surgery, Washington University in Saint Louis School of Medicine, Saint Louis, Missouri, USA
| | - Christina A Gurnett
- Department of Neurology, Washington University in Saint Louis School of Medicine, Saint Louis, Missouri, USA
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9
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Zhang S, Chasman D, Knaack S, Roy S. In silico prediction of high-resolution Hi-C interaction matrices. Nat Commun 2019; 10:5449. [PMID: 31811132 PMCID: PMC6898380 DOI: 10.1038/s41467-019-13423-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/07/2019] [Indexed: 11/28/2022] Open
Abstract
The three-dimensional (3D) organization of the genome plays an important role in gene regulation bringing distal sequence elements in 3D proximity to genes hundreds of kilobases away. Hi-C is a powerful genome-wide technique to study 3D genome organization. Owing to experimental costs, high resolution Hi-C datasets are limited to a few cell lines. Computational prediction of Hi-C counts can offer a scalable and inexpensive approach to examine 3D genome organization across multiple cellular contexts. Here we present HiC-Reg, an approach to predict contact counts from one-dimensional regulatory signals. HiC-Reg predictions identify topologically associating domains and significant interactions that are enriched for CCCTC-binding factor (CTCF) bidirectional motifs and interactions identified from complementary sources. CTCF and chromatin marks, especially repressive and elongation marks, are most important for HiC-Reg’s predictive performance. Taken together, HiC-Reg provides a powerful framework to generate high-resolution profiles of contact counts that can be used to study individual locus level interactions and higher-order organizational units of the genome. Existing computational approaches to predict long-range regulatory interactions do not fully exploit high-resolution Hi-C datasets. Here the authors present a Random Forests regression-based approach to predict high-resolution Hi-C counts using one-dimensional regulatory genomic signals.
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Affiliation(s)
- Shilu Zhang
- Wisconsin Institute for Discovery, 330 North Orchard Street, Madison, WI, 53715, USA
| | - Deborah Chasman
- Wisconsin Institute for Discovery, 330 North Orchard Street, Madison, WI, 53715, USA
| | - Sara Knaack
- Wisconsin Institute for Discovery, 330 North Orchard Street, Madison, WI, 53715, USA
| | - Sushmita Roy
- Wisconsin Institute for Discovery, 330 North Orchard Street, Madison, WI, 53715, USA. .,Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, 53715, USA.
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10
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Schluth-Bolard C, Diguet F, Chatron N, Rollat-Farnier PA, Bardel C, Afenjar A, Amblard F, Amiel J, Blesson S, Callier P, Capri Y, Collignon P, Cordier MP, Coubes C, Demeer B, Chaussenot A, Demurger F, Devillard F, Doco-Fenzy M, Dupont C, Dupont JM, Dupuis-Girod S, Faivre L, Gilbert-Dussardier B, Guerrot AM, Houlier M, Isidor B, Jaillard S, Joly-Hélas G, Kremer V, Lacombe D, Le Caignec C, Lebbar A, Lebrun M, Lesca G, Lespinasse J, Levy J, Malan V, Mathieu-Dramard M, Masson J, Masurel-Paulet A, Mignot C, Missirian C, Morice-Picard F, Moutton S, Nadeau G, Pebrel-Richard C, Odent S, Paquis-Flucklinger V, Pasquier L, Philip N, Plutino M, Pons L, Portnoï MF, Prieur F, Puechberty J, Putoux A, Rio M, Rooryck-Thambo C, Rossi M, Sarret C, Satre V, Siffroi JP, Till M, Touraine R, Toutain A, Toutain J, Valence S, Verloes A, Whalen S, Edery P, Tabet AC, Sanlaville D. Whole genome paired-end sequencing elucidates functional and phenotypic consequences of balanced chromosomal rearrangement in patients with developmental disorders. J Med Genet 2019; 56:526-535. [PMID: 30923172 DOI: 10.1136/jmedgenet-2018-105778] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/30/2019] [Accepted: 02/20/2019] [Indexed: 11/04/2022]
Abstract
BACKGROUND Balanced chromosomal rearrangements associated with abnormal phenotype are rare events, but may be challenging for genetic counselling, since molecular characterisation of breakpoints is not performed routinely. We used next-generation sequencing to characterise breakpoints of balanced chromosomal rearrangements at the molecular level in patients with intellectual disability and/or congenital anomalies. METHODS Breakpoints were characterised by a paired-end low depth whole genome sequencing (WGS) strategy and validated by Sanger sequencing. Expression study of disrupted and neighbouring genes was performed by RT-qPCR from blood or lymphoblastoid cell line RNA. RESULTS Among the 55 patients included (41 reciprocal translocations, 4 inversions, 2 insertions and 8 complex chromosomal rearrangements), we were able to detect 89% of chromosomal rearrangements (49/55). Molecular signatures at the breakpoints suggested that DNA breaks arose randomly and that there was no major influence of repeated elements. Non-homologous end-joining appeared as the main mechanism of repair (55% of rearrangements). A diagnosis could be established in 22/49 patients (44.8%), 15 by gene disruption (KANSL1, FOXP1, SPRED1, TLK2, MBD5, DMD, AUTS2, MEIS2, MEF2C, NRXN1, NFIX, SYNGAP1, GHR, ZMIZ1) and 7 by position effect (DLX5, MEF2C, BCL11B, SATB2, ZMIZ1). In addition, 16 new candidate genes were identified. Systematic gene expression studies further supported these results. We also showed the contribution of topologically associated domain maps to WGS data interpretation. CONCLUSION Paired-end WGS is a valid strategy and may be used for structural variation characterisation in a clinical setting.
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Affiliation(s)
- Caroline Schluth-Bolard
- Service de Génétique, Hospices Civils de Lyon, Bron, France.,INSERM U1028, CNRS UMR5292, UCBL1, GENDEV Team, Neurosciences Research Center of Lyon, Bron, France
| | - Flavie Diguet
- Service de Génétique, Hospices Civils de Lyon, Bron, France.,INSERM U1028, CNRS UMR5292, UCBL1, GENDEV Team, Neurosciences Research Center of Lyon, Bron, France
| | - Nicolas Chatron
- Service de Génétique, Hospices Civils de Lyon, Bron, France.,INSERM U1028, CNRS UMR5292, UCBL1, GENDEV Team, Neurosciences Research Center of Lyon, Bron, France
| | | | - Claire Bardel
- Cellule bioinformatique de la plateforme NGS, Hospices Civils de Lyon, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR5558, Lyon 1 University, Bron, France
| | - Alexandra Afenjar
- Département de génétique et embryologie médicale, Centre de référence des déficiences intellectuelles de causes rares, AP-HP, Hôpital Armand Trousseau, Paris, France.,GRC n°19, pathologies Congénitales du Cervelet-LeucoDystrophies, AP-HP, Hôpital Armand Trousseau, Sorbonne Université, Paris, France
| | - Florence Amblard
- Laboratoire de Génétique Chromosomique, Hôpital Couple Enfant, CHU Grenoble, Grenoble, France
| | - Jeanne Amiel
- Service de Génétique Médicale, Hôpital Necker-Enfants Malades, Paris, France
| | | | | | - Yline Capri
- Département de Génétique, Hôpital Robert Debré, Paris, France
| | | | | | - Christine Coubes
- Service de Génétique, Hôpital Arnaud de Villeneuve, Montpellier, France
| | - Benedicte Demeer
- Centre d'activité de génétique clinique, CLAD nord de France, CHU Amiens, Amiens, France
| | | | | | - Françoise Devillard
- Laboratoire de Génétique Chromosomique, Hôpital Couple Enfant, CHU Grenoble, Grenoble, France
| | | | - Céline Dupont
- Département de Génétique, Hôpital Robert Debré, Paris, France
| | - Jean-Michel Dupont
- Laboratoire de Cytogénétique Constitutionnelle, APHP-HUPC site Cochin, Paris, France
| | | | - Laurence Faivre
- Centre de référence anomalies du développement et syndromes malformatifs, FHU TRANSLAD et équipe GAD INSERM UMR1231, CHU Dijon-Bourgogne et Université de Bourgogne-Franche Comté, Dijon, France
| | | | | | - Marine Houlier
- Service de Génétique Médicale, Hôpital Necker-Enfants Malades, Paris, France
| | | | - Sylvie Jaillard
- Laboratoire de Cytogénétique et de Biologie Cellulaire, CHU Pontchaillou, Rennes, France
| | | | - Valérie Kremer
- Laboratoire de Cytogénétique, CHU Strasbourg, Strasbourg, France
| | - Didier Lacombe
- Service de Génétique Médicale, Hôpital Pellegrin, Université de Bordeaux, MRGM INSERM U1211, CHU Bordeaux, Bordeaux, France
| | | | - Aziza Lebbar
- Laboratoire de Cytogénétique Constitutionnelle, APHP-HUPC site Cochin, Paris, France
| | - Marine Lebrun
- Service de Génétique Clinique, Chromosomique et Moléculaire, CHU Hôpital Nord, Saint-Etienne, France
| | - Gaetan Lesca
- Service de Génétique, Hospices Civils de Lyon, Bron, France.,INSERM U1028, CNRS UMR5292, UCBL1, GENDEV Team, Neurosciences Research Center of Lyon, Bron, France
| | - James Lespinasse
- Laboratoire de Génétique Chromosomique, CH Général, Chambéry, France
| | - Jonathan Levy
- Département de Génétique, Hôpital Robert Debré, Paris, France
| | - Valérie Malan
- Service de Cytogénétique, Hôpital Necker Enfants Malades, Paris, France
| | | | - Julie Masson
- Service de Génétique, Hospices Civils de Lyon, Bron, France.,INSERM U1028, CNRS UMR5292, UCBL1, GENDEV Team, Neurosciences Research Center of Lyon, Bron, France
| | - Alice Masurel-Paulet
- Centre de référence anomalies du développement et syndromes malformatifs, FHU TRANSLAD et équipe GAD INSERM UMR1231, CHU Dijon-Bourgogne et Université de Bourgogne-Franche Comté, Dijon, France
| | - Cyril Mignot
- Département de Génétique; Centre de Référence Déficience Intellectuelle de Causes Rares, Groupe Hospitalier Pitié-Salpêtrière, APHP, Paris, France
| | - Chantal Missirian
- Laboratoire de Génétique Chromosomique, Département de Génétique Médicale, AP-HM, Marseille, France
| | - Fanny Morice-Picard
- Service de Génétique Médicale, Hôpital Pellegrin, Université de Bordeaux, MRGM INSERM U1211, CHU Bordeaux, Bordeaux, France
| | - Sébastien Moutton
- Service de Génétique Médicale, Hôpital Pellegrin, Université de Bordeaux, MRGM INSERM U1211, CHU Bordeaux, Bordeaux, France
| | - Gwenaël Nadeau
- Laboratoire de Génétique Chromosomique, CH Général, Chambéry, France.,Service de Cytogénétique, CH Valence, Valence, France
| | - Céline Pebrel-Richard
- Service de Cytogénétique Médicale, Hôpital Estaing, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Sylvie Odent
- Service de Génétique Clinique, CHU Rennes, Rennes, France.,CNRS, IGDR (Institut de Génétique et Développement de Rennes) UMR 6290, Université de Rennes, Rennes, France
| | | | | | - Nicole Philip
- Département de Génétique Médicale, Unité de Génétique Clinique, AP-HM, Marseille, France
| | | | - Linda Pons
- Service de Génétique, Hospices Civils de Lyon, Bron, France.,INSERM U1028, CNRS UMR5292, UCBL1, GENDEV Team, Neurosciences Research Center of Lyon, Bron, France
| | - Marie-France Portnoï
- Département de génétique et embryologie médicale, Centre de référence des déficiences intellectuelles de causes rares, AP-HP, Hôpital Armand Trousseau, Paris, France
| | - Fabienne Prieur
- Service de Génétique Clinique, Chromosomique et Moléculaire, CHU Hôpital Nord, Saint-Etienne, France
| | | | - Audrey Putoux
- Service de Génétique, Hospices Civils de Lyon, Bron, France.,INSERM U1028, CNRS UMR5292, UCBL1, GENDEV Team, Neurosciences Research Center of Lyon, Bron, France
| | - Marlène Rio
- Service de Génétique Médicale, Hôpital Necker-Enfants Malades, Paris, France
| | - Caroline Rooryck-Thambo
- Service de Génétique Médicale, Hôpital Pellegrin, Université de Bordeaux, MRGM INSERM U1211, CHU Bordeaux, Bordeaux, France
| | - Massimiliano Rossi
- Service de Génétique, Hospices Civils de Lyon, Bron, France.,INSERM U1028, CNRS UMR5292, UCBL1, GENDEV Team, Neurosciences Research Center of Lyon, Bron, France
| | - Catherine Sarret
- Service de Génétique Médicale, Hôpital Estaing, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Véronique Satre
- Laboratoire de Génétique Chromosomique, Hôpital Couple Enfant, CHU Grenoble, Grenoble, France.,Equipe Génétique, Epigénétique et Thérapies de l'Infertilité, IAB, INSERM 1209, CNRS UMR5309, Grenoble, France
| | - Jean-Pierre Siffroi
- Département de génétique et embryologie médicale, Centre de référence des déficiences intellectuelles de causes rares, AP-HP, Hôpital Armand Trousseau, Paris, France
| | - Marianne Till
- Service de Génétique, Hospices Civils de Lyon, Bron, France
| | - Renaud Touraine
- Service de Génétique Clinique, Chromosomique et Moléculaire, CHU Hôpital Nord, Saint-Etienne, France
| | | | - Jérome Toutain
- Service de Génétique Médicale, Hôpital Pellegrin, Université de Bordeaux, MRGM INSERM U1211, CHU Bordeaux, Bordeaux, France
| | - Stéphanie Valence
- GRC n°19, pathologies Congénitales du Cervelet-LeucoDystrophies, AP-HP, Hôpital Armand Trousseau, Sorbonne Université, Paris, France.,Service de Neurologie Pédiatrique, Hôpital Armand Trousseau, APHP, GHUEP, Paris, France
| | - Alain Verloes
- Département de Génétique, Hôpital Robert Debré, Paris, France
| | - Sandra Whalen
- Département de génétique et embryologie médicale, Centre de référence des déficiences intellectuelles de causes rares, AP-HP, Hôpital Armand Trousseau, Paris, France
| | - Patrick Edery
- Service de Génétique, Hospices Civils de Lyon, Bron, France.,INSERM U1028, CNRS UMR5292, UCBL1, GENDEV Team, Neurosciences Research Center of Lyon, Bron, France
| | | | - Damien Sanlaville
- Service de Génétique, Hospices Civils de Lyon, Bron, France.,INSERM U1028, CNRS UMR5292, UCBL1, GENDEV Team, Neurosciences Research Center of Lyon, Bron, France
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11
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Versatility of multivalent orientation, inverted meiosis, and rescued fitness in holocentric chromosomal hybrids. Proc Natl Acad Sci U S A 2018; 115:E9610-E9619. [PMID: 30266792 DOI: 10.1073/pnas.1802610115] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Chromosomal rearrangements (e.g., fusions/fissions) have the potential to drive speciation. However, their accumulation in a population is generally viewed as unlikely, because chromosomal heterozygosity should lead to meiotic problems and aneuploid gametes. Canonical meiosis involves segregation of homologous chromosomes in meiosis I and sister chromatid segregation during meiosis II. In organisms with holocentric chromosomes, which are characterized by kinetic activity distributed along almost the entire chromosome length, this order may be inverted depending on their metaphase I orientation. Here we analyzed the evolutionary role of this intrinsic versatility of holocentric chromosomes, which is not available to monocentric ones, by studying F1 to F4 hybrids between two chromosomal races of the Wood White butterfly (Leptidea sinapis), separated by at least 24 chromosomal fusions/fissions. We found that these chromosomal rearrangements resulted in multiple meiotic multivalents, and, contrary to the theoretical prediction, the hybrids displayed relatively high reproductive fitness (42% of that of the control lines) and regular behavior of meiotic chromosomes. In the hybrids, we also discovered inverted meiosis, in which the first and critical stage of chromosome number reduction was replaced by the less risky stage of sister chromatid separation. We hypothesize that the ability to invert the order of the main meiotic events facilitates proper chromosome segregation and hence rescues fertility and viability in chromosomal hybrids, potentially promoting dynamic karyotype evolution and chromosomal speciation.
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12
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Cutrupi AN, Brewer MH, Nicholson GA, Kennerson M. Structural variations causing inherited peripheral neuropathies: A paradigm for understanding genomic organization, chromatin interactions, and gene dysregulation. Mol Genet Genomic Med 2018; 6:422-433. [PMID: 29573232 PMCID: PMC6014456 DOI: 10.1002/mgg3.390] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/09/2018] [Accepted: 03/01/2018] [Indexed: 11/16/2022] Open
Abstract
Inherited peripheral neuropathies (IPNs) are a clinically and genetically heterogeneous group of diseases affecting the motor and sensory peripheral nerves. IPNs have benefited from gene discovery and genetic diagnosis using next-generation sequencing with over 80 causative genes available for testing. Despite this success, up to 50% of cases remain genetically unsolved. In the absence of protein coding mutations, noncoding DNA or structural variation (SV) mutations are a possible explanation. The most common IPN, Charcot-Marie-Tooth neuropathy type 1A (CMT1A), is caused by a 1.5 Mb duplication causing trisomy of the dosage sensitive gene PMP22. Using genome sequencing, we recently identified two large genomic rearrangements causing IPN subtypes X-linked CMT (CMTX3) and distal hereditary motor neuropathy (DHMN1), thereby expanding the spectrum of SV mutations causing IPN. Understanding how newly discovered SVs can cause IPN may serve as a useful paradigm to examine the role of topologically associated domains (TADs), chromatin interactions, and gene dysregulation in disease. This review will describe the growing role of SV in the pathogenesis of IPN and the importance of considering this type of mutation in Mendelian diseases where protein coding mutations cannot be identified.
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Affiliation(s)
- Anthony N. Cutrupi
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
| | - Megan H. Brewer
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
| | - Garth A. Nicholson
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
- Molecular Medicine LaboratoryConcord HospitalSydneyNSWAustralia
| | - Marina L. Kennerson
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
- Molecular Medicine LaboratoryConcord HospitalSydneyNSWAustralia
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13
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Łopacińska-Jørgensen JM, Pedersen JN, Bak M, Mehrjouy MM, Sørensen KT, Østergaard PF, Bilenberg B, Kristensen A, Taboryski RJ, Flyvbjerg H, Marie R, Tommerup N, Silahtaroglu A. Enrichment of megabase-sized DNA molecules for single-molecule optical mapping and next-generation sequencing. Sci Rep 2017; 7:17893. [PMID: 29263336 PMCID: PMC5738345 DOI: 10.1038/s41598-017-18091-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 12/06/2017] [Indexed: 11/23/2022] Open
Abstract
Next-generation sequencing (NGS) has caused a revolution, yet left a gap: long-range genetic information from native, non-amplified DNA fragments is unavailable. It might be obtained by optical mapping of megabase-sized DNA molecules. Frequently only a specific genomic region is of interest, so here we introduce a method for selection and enrichment of megabase-sized DNA molecules intended for single-molecule optical mapping: DNA from a human cell line is digested by the NotI rare-cutting enzyme and size-selected by pulsed-field gel electrophoresis. For demonstration, more than 600 sub-megabase- to megabase-sized DNA molecules were recovered from the gel and analysed by denaturation-renaturation optical mapping. Size-selected molecules from the same gel were sequenced by NGS. The optically mapped molecules and the NGS reads showed enrichment from regions defined by NotI restriction sites. We demonstrate that the unannotated genome can be characterized in a locus-specific manner via molecules partially overlapping with the annotated genome. The method is a promising tool for investigation of structural variants in enriched human genomic regions for both research and diagnostic purposes. Our enrichment method could potentially work with other genomes or target specified regions by applying other genomic editing tools, such as the CRISPR/Cas9 system.
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Affiliation(s)
- Joanna M Łopacińska-Jørgensen
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Alle 14, Copenhagen, 2200, Denmark
| | - Jonas N Pedersen
- Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads 345a, Kongens Lyngby, 2800, Denmark
| | - Mads Bak
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Alle 14, Copenhagen, 2200, Denmark
| | - Mana M Mehrjouy
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Alle 14, Copenhagen, 2200, Denmark
| | - Kristian T Sørensen
- Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads 345a, Kongens Lyngby, 2800, Denmark
| | - Peter F Østergaard
- Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads 345a, Kongens Lyngby, 2800, Denmark
| | - Brian Bilenberg
- NIL Technology ApS, Diplomvej 381, Kongens Lyngby, 2800, Denmark
| | - Anders Kristensen
- Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads 345a, Kongens Lyngby, 2800, Denmark
| | - Rafael J Taboryski
- Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads 345a, Kongens Lyngby, 2800, Denmark
| | - Henrik Flyvbjerg
- Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads 345a, Kongens Lyngby, 2800, Denmark
| | - Rodolphe Marie
- Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads 345a, Kongens Lyngby, 2800, Denmark
| | - Niels Tommerup
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Alle 14, Copenhagen, 2200, Denmark
| | - Asli Silahtaroglu
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Alle 14, Copenhagen, 2200, Denmark.
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14
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Digging for known genetic mutations underlying inherited bone and cartilage characteristics and disorders in the dog and cat. Vet Comp Orthop Traumatol 2017; 29:269-76. [DOI: 10.3415/vcot-16-02-0037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 04/18/2016] [Indexed: 12/16/2022]
Abstract
SummaryGene mapping projects for many traits in both dogs and cats have yielded new knowledge. Both researchers and the public alike have been fascinated by the inheritance of breed characteristic phenotypes and sporadic disorders. It has been proposed that selective breeding practices have on occasion generated alterations in structure that might be harmful. In this review, simply inherited disorders and characteristics affecting bone and cartilage for which a putative mutation is known are collected. A better understanding of the known inherited basis of skeletal conditions and disorders will assist veterinarians to improve their diagnoses and increase their effectiveness on advising clients on the prevention, management, prognosis and possible treatment of the conditions.
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15
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Podolska A, Kobelt A, Fuchs S, Hackmann K, Rump A, Schröck E, Kutsche K, Di Donato N. Functional monosomy of 6q27-qter and functional disomy of Xpter-p22.11 due to X;6 translocation with an atypical X-inactivation pattern. Am J Med Genet A 2017; 173:1334-1341. [PMID: 28371302 DOI: 10.1002/ajmg.a.38183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 12/20/2016] [Accepted: 01/26/2017] [Indexed: 12/20/2022]
Abstract
Pattern of X chromosome inactivation (XCI) is typically random in females. However, chromosomal rearrangements affecting the X chromosome can result in XCI skewing due to cell growth disadvantage. In case of an X;autosome translocation, this usually leads to an XCI pattern of 100:0 with the derivative X being the active one in the majority of females. A de novo balanced X;6 translocation [46,X,t(X;6)(p22.1;q27)] and a completely skewed XCI pattern (100:0) were detected in a female patient with microcephaly, cerebellar vermis hypoplasia, heart defect, and severe developmental delay. We mapped the breakpoint regions using fluorescence in situ hybridization and found the X-linked gene POLA1 to be disrupted. POLA1 codes for the catalytic subunit of the polymerase α-primase complex which is responsible for initiation of the DNA replication process; absence of POLA1 is probably incompatible with life. Consequently, by RBA banding we determined which of the X chromosomes was the active one in the patient. In all examined lymphocytes the wild-type X chromosome was active. We propose that completely skewed XCI favoring the normal X chromosome resulted from death of cells with an active derivative X that was caused by a non-functional POLA1 gene. In summary, we conclude that functional monosomy of 6q27-qter and functional disomy of Xpter-p22.11 are responsible for the clinical phenotype of the patient. This case demonstrates the importance of determining which one of the X chromosomes underwent inactivation to correlate clinical features of a female with an X;autosome translocation with the nature of the genetic alteration.
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Affiliation(s)
- Anna Podolska
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Sigrid Fuchs
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Karl Hackmann
- Institute for Clinical Genetics, TU Dresden, Dresden, Germany
| | - Andreas Rump
- Institute for Clinical Genetics, TU Dresden, Dresden, Germany
| | - Evelin Schröck
- Institute for Clinical Genetics, TU Dresden, Dresden, Germany
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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16
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Liu H, Luo X, Niu L, Xiao Y, Chen L, Liu J, Wang X, Jin M, Li W, Zhang Q, Yan J. Distant eQTLs and Non-coding Sequences Play Critical Roles in Regulating Gene Expression and Quantitative Trait Variation in Maize. MOLECULAR PLANT 2017; 10:414-426. [PMID: 27381443 DOI: 10.1016/j.molp.2016.06.016] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/23/2016] [Accepted: 06/27/2016] [Indexed: 05/20/2023]
Abstract
A detailed understanding of genetic architecture of mRNA expression by millions of genetic variants is important for studying quantitative trait variation. In this study, we identified 1.25M SNPs with a minor allele frequency greater than 0.05 by combining reduced genome sequencing (GBS), high-density array technologies (600K), and previous deep RNA-sequencing data from 368 diverse inbred lines of maize. The balanced allelic frequencies and distributions in a relatively large and diverse natural panel helped to identify expression quantitative trait loci (eQTLs) associated with more than 18 000 genes (63.4% of tested genes). We found that distant eQTLs were more frequent (∼75% of all eQTLs) across the whole genome. Thirteen novel associated loci affecting maize kernel oil concentration were identified using the new dataset, among which one intergenic locus affected the kernel oil variation by controlling expression of three other known oil-related genes. Altogether, this study provides resources for expanding our understanding of cellular regulatory mechanisms of transcriptome variation and the landscape of functional variants within the maize genome, thereby enhancing the understanding of quantitative variations.
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Affiliation(s)
- Haijun Liu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Xin Luo
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Luyao Niu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Yingjie Xiao
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Lu Chen
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Jie Liu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiaqing Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Minliang Jin
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Wenqiang Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Qinghua Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Jianbing Yan
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
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Vockley CM, Barrera A, Reddy TE. Decoding the role of regulatory element polymorphisms in complex disease. Curr Opin Genet Dev 2016; 43:38-45. [PMID: 27984826 DOI: 10.1016/j.gde.2016.10.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 10/24/2016] [Indexed: 11/29/2022]
Abstract
Genetic variation in gene regulatory elements contributes to diverse human diseases, ranging from rare and severe developmental defects to common and complex diseases such as obesity and diabetes. Early examples of regulatory mechanisms of human diseases involve large chromosomal rearrangements that change the regulatory connections within the genome. Single nucleotide variants in regulatory elements can also contribute to disease, potentially via demonstrated associations with changes in transcription factor binding, enhancer activity, post-translational histone modifications, long-range enhancer-promoter interactions, or RNA polymerase recruitment. Establishing causality between non-coding genetic variants, gene regulation, and disease has recently become more feasible with advances in genome-editing and epigenome-editing technologies. As establishing causal regulatory mechanisms of diseases becomes routine, functional annotation of target genes is likely to emerge as a major bottleneck for translation into patient benefits. In this review, we discuss the history and recent advances in understanding the regulatory mechanisms of human disease, and new challenges likely to be encountered once establishing those mechanisms becomes rote.
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Affiliation(s)
- Christopher M Vockley
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, United States; Department of Biostatistics & Bioinformatics, and Center for Genomic & Computational Biology, Duke University Medical Center, Durham, NC 27710, United States
| | - Alejandro Barrera
- Department of Biostatistics & Bioinformatics, and Center for Genomic & Computational Biology, Duke University Medical Center, Durham, NC 27710, United States
| | - Timothy E Reddy
- Department of Biostatistics & Bioinformatics, and Center for Genomic & Computational Biology, Duke University Medical Center, Durham, NC 27710, United States.
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18
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Fang Y, Wang L, Wang X, You Q, Pan X, Xiao J, Wang XE, Wu Y, Su Z, Zhang W. Histone modifications facilitate the coexpression of bidirectional promoters in rice. BMC Genomics 2016; 17:768. [PMID: 27716056 PMCID: PMC5045660 DOI: 10.1186/s12864-016-3125-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 09/26/2016] [Indexed: 12/27/2022] Open
Abstract
Background Bidirectional gene pairs are highly abundant and mostly co-regulated in eukaryotic genomes. The structural features of bidirectional promoters (BDPs) have been well studied in yeast, humans and plants. However, the underlying mechanisms responsible for the coexpression of BDPs remain understudied, especially in plants. Results Here, we characterized chromatin features associated with rice BDPs. Several unique chromatin features were present in rice BDPs but were missing from unidirectional promoters (UDPs), including overrepresented active histone marks, canonical nucleosomes and underrepresented H3K27me3. In particular, overrepresented active marks (H3K4ac, H4K12ac, H4K16ac, H3K4me2 and H3K36me3) were truly overrepresented in type I BDPs but not in the other two BDPs, based on a Kolmogorov-Smirnov test. Conclusions Our analyses indicate that active marks (H3K4ac, H4K12ac, H4K16ac, H3K4me3, H3K9ac and H3K27ac) may coordinate with repressive marks (H3K27me3 and H3K9me1/3) to build a unique chromatin structure that favors the coregulation of bidirectional gene pairs. Thus, our findings help to enhance the understanding of unique epigenetic mechanisms that regulate bidirectional gene pairs and may improve the manipulation of gene pairs for crop bioengineering. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3125-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yuan Fang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agriculture University, Nanjing, Jiangsu, 210095, China
| | - Lei Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agriculture University, Nanjing, Jiangsu, 210095, China
| | - Ximeng Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agriculture University, Nanjing, Jiangsu, 210095, China
| | - Qi You
- State Key Laboratory of Plant Physiology and Biochemistry, CBS, China Agricultural University, Beijing, 100193, China
| | - Xiucai Pan
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agriculture University, Nanjing, Jiangsu, 210095, China
| | - Jin Xiao
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agriculture University, Nanjing, Jiangsu, 210095, China
| | - Xiu-E Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agriculture University, Nanjing, Jiangsu, 210095, China
| | - Yufeng Wu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agriculture University, Nanjing, Jiangsu, 210095, China
| | - Zhen Su
- State Key Laboratory of Plant Physiology and Biochemistry, CBS, China Agricultural University, Beijing, 100193, China.
| | - Wenli Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agriculture University, Nanjing, Jiangsu, 210095, China. .,JiangSu Collaborative Innovation Center for Modern Crop Production (JCIC-MCP), Nanjing Agriculture University, Nanjing, Jiangsu, 210095, China.
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19
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Functional characterization of open chromatin in bidirectional promoters of rice. Sci Rep 2016; 6:32088. [PMID: 27558448 PMCID: PMC4997330 DOI: 10.1038/srep32088] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 08/02/2016] [Indexed: 02/05/2023] Open
Abstract
Bidirectional gene pairs tend to be highly coregulated and function in similar biological processes in eukaryotic genomes. Structural features and functional consequences of bidirectional promoters (BDPs) have received considerable attention among diverse species. However, the underlying mechanisms responsible for the bidirectional transcription and coexpression of BDPs remain poorly understood in plants. In this study, we integrated DNase-seq, RNA-seq, ChIP-seq and MNase-seq data and investigated the effect of physical DNase I hypersensitive site (DHS) positions on the transcription of rice BDPs. We found that the physical position of a DHS relative to the TSS of bidirectional gene pairs can affect the expression of the corresponding genes: the closer a DHS is to the TSS, the higher is the expression level of the genes. Most importantly, we observed that the distribution of DHSs plays a significant role in the regulation of transcription and the coexpression of gene pairs, which are possibly mediated by orchestrating the positioning of histone marks and canonical nucleosomes around BDPs. Our results demonstrate that the combined actions of chromatin structures with DHSs, which contain functional cis-elements for interaction with transcriptional machinery, may play an important role in the regulation of the bidirectional transcription or coexpression in rice BDPs. Our findings may help to enhance the understanding of DHSs in the regulation of bidirectional gene pairs.
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20
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Amarillo IE, Nievera I, Hagan A, Huchthagowder V, Heeley J, Hollander A, Koenig J, Austin P, Wang T. Integrated small copy number variations and epigenome maps of disorders of sex development. Hum Genome Var 2016; 3:16012. [PMID: 27340555 PMCID: PMC4899613 DOI: 10.1038/hgv.2016.12] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/24/2016] [Accepted: 03/26/2016] [Indexed: 02/03/2023] Open
Abstract
Small copy number variations (CNVs) have typically not been analyzed or reported in clinical settings and hence have remained underrepresented in databases and the literature. Here, we focused our investigations on these small CNVs using chromosome microarray analysis (CMA) data previously obtained from patients with atypical characteristics or disorders of sex development (DSD). Using our customized CMA track targeting 334 genes involved in the development of urogenital and reproductive structures and a less stringent analysis filter, we uncovered small genes with recurrent and overlapping CNVs as small as 1 kb, and small regions of homozygosity (ROHs), imprinting and position effects. Detailed analysis of these high-resolution data revealed CNVs and ROHs involving structural and functional domains, repeat elements, active transcription sites and regulatory regions. Integration of these genomic data with DNA methylation, histone modification and predicted RNA expression profiles in normal testes and ovaries suggested spatiotemporal and tissue-specific gene regulation. This study emphasized a DSD-specific and gene-targeted CMA approach that uncovered previously unanalyzed or unreported small genes and CNVs, contributing to the growing resources on small CNVs and facilitating the narrowing of the genomic gap for identifying candidate genes or regions. This high-resolution analysis tool could improve the diagnostic utility of CMA, not only in patients with DSD but also in other clinical populations. These integrated data provided a better genomic-epigenomic landscape of DSD and greater opportunities for downstream research.
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Affiliation(s)
- Ina E Amarillo
- Cytogenomics and Molecular Pathology Laboratory, Division of Laboratory and Genomic Medicine, Department of Pathology and Immunology, Washington University in St Louis School of Medicine, St Louis, MO, USA; Washington University in St Louis School of Medicine DSD Team, St Louis, MO, USA
| | - Isabelle Nievera
- Washington University in St Louis School of Medicine DSD Team , St Louis, MO, USA
| | - Andrew Hagan
- Division of Biology and Biomedical Sciences, Washington University in St Louis , St Louis, MO, USA
| | - Vishwa Huchthagowder
- Cytogenomics and Molecular Pathology Laboratory, Division of Laboratory and Genomic Medicine, Department of Pathology and Immunology, Washington University in St Louis School of Medicine , St Louis, MO, USA
| | - Jennifer Heeley
- Washington University in St Louis School of Medicine DSD Team, St Louis, MO, USA; Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Abby Hollander
- Washington University in St Louis School of Medicine DSD Team, St Louis, MO, USA; Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Joel Koenig
- Washington University in St Louis School of Medicine DSD Team, St Louis, MO, USA; Department of Surgery, Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Paul Austin
- Washington University in St Louis School of Medicine DSD Team, St Louis, MO, USA; Department of Surgery, Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Ting Wang
- Department of Genetics, Washington University in St Louis School of Medicine , St Louis, MO, USA
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21
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Bagadia M, Singh A, Singh Sandhu K. Three Dimensional Organization of Genome Might Have Guided the Dynamics of Gene Order Evolution in Eukaryotes. Genome Biol Evol 2016; 8:946-54. [PMID: 26957031 PMCID: PMC4824123 DOI: 10.1093/gbe/evw050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In eukaryotes, genes are nonrandomly organized into short gene-dense regions or "gene-clusters" interspersed by long gene-poor regions. How these gene-clusters have evolved is not entirely clear. Gene duplication may not account for all the gene-clusters since the genes in most of the clusters do not exhibit significant sequence similarity. In this study, using genome-wide data sets from budding yeast, fruit-fly, and human, we show that: 1) long-range evolutionary repositioning of genes strongly associate with their spatial proximity in the nucleus; 2) presence of evolutionary DNA break-points at involved loci hints at their susceptibility to undergo long-range genomic rearrangements; and 3) correlated epigenetic and transcriptional states of engaged genes highlight the underlying evolutionary constraints. The significance of observation 1, 2, and 3 are particularly stronger for the instances of inferred evolutionary gain, as compared with loss, of linear gene-clustering. These observations suggest that the long-range genomic rearrangements guided through 3D genome organization might have contributed to the evolution of gene order. We further hypothesize that the evolution of linear gene-clusters in eukaryotic genomes might have been mediated through spatial interactions among distant loci in order to optimize co-ordinated regulation of genes. We model this hypothesis through a heuristic model of gene-order evolution.
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Affiliation(s)
- Meenakshi Bagadia
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, SAS Nagar 140306, India
| | - Arashdeep Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, SAS Nagar 140306, India
| | - Kuljeet Singh Sandhu
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, SAS Nagar 140306, India
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22
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Moorthy SD, Mitchell JA. Generating CRISPR/Cas9 Mediated Monoallelic Deletions to Study Enhancer Function in Mouse Embryonic Stem Cells. J Vis Exp 2016:e53552. [PMID: 27078492 DOI: 10.3791/53552] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Enhancers control cell identity by regulating tissue-specific gene expression in a position and orientation independent manner. These enhancers are often located distally from the regulated gene in intergenic regions or even within the body of another gene. The position independent nature of enhancer activity makes it difficult to match enhancers with the genes they regulate. Deletion of an enhancer region provides direct evidence for enhancer activity and is the gold standard to reveal an enhancer's role in endogenous gene transcription. Conventional homologous recombination based deletion methods have been surpassed by recent advances in genome editing technology which enable rapid and precisely located changes to the genomes of numerous model organisms. CRISPR/Cas9 mediated genome editing can be used to manipulate the genome in many cell types and organisms rapidly and cost effectively, due to the ease with which Cas9 can be targeted to the genome by a guide RNA from a bespoke expression plasmid. Homozygous deletion of essential gene regulatory elements might lead to lethality or alter cellular phenotype whereas monoallelic deletion of transcriptional enhancers allows for the study of cis-regulation of gene expression without this confounding issue. Presented here is a protocol for CRISPR/Cas9 mediated deletion in F1 mouse embryonic stem (ES) cells (Mus musculus(129) x Mus castaneus). Monoallelic deletion, screening and expression analysis is facilitated by single nucleotide polymorphisms (SNP) between the two alleles which occur on average every 125 bp in these cells.
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23
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Fonseca ACS, Bonaldi A, Fonseca SAS, Otto PA, Kok F, Bak M, Tommerup N, Vianna-Morgante AM. The segregation of different submicroscopic imbalances underlying the clinical variability associated with a familial karyotypically balanced translocation. Mol Cytogenet 2015; 8:106. [PMID: 26719771 PMCID: PMC4696321 DOI: 10.1186/s13039-015-0205-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 12/18/2015] [Indexed: 12/21/2022] Open
Abstract
Background About 7 % of karyotypically balanced chromosomal rearrangements (BCRs) are associated with congenital anomalies due to gene or regulatory element disruption, and cryptic imbalances on rearranged chromosomes. Rare familial BCRs segregating with clinical features are a powerful source for the identifying of causative genes due to the presence of several affected carriers. Case presentation We report on a karyotypically balanced translocation t(2;22)(p13;q12.2) associated with variable learning disabilities, and craniofacial and hand dysmorphisms, detected in six individuals in a three-generation family. Combined a-CGH, FISH and mate-pair sequencing revealed a ten-break complex rearrangement, also involving chromosome 5. As the consequence of the segregation of the derivative chromosomes der(2), der(5) and der(22), different imbalances were present in affected and clinically normal family members, thus contributing to the clinical variability. A 6.64 Mb duplication of a 5q23.2-23.3 segment was the imbalance common to all affected individuals. Although LMNB1, implicated in adult-onset autosomal dominant leukodystrophy (ADLD) when overexpressed, was among the 18 duplicated genes, none of the adult carriers manifested ADLD, and LMNB1 overexpression was not detected in the two tested individuals, after qRT-PCR. The ectopic location of the extra copy of the LMBN1 gene on chromosome 22 might have negatively impacted its expression. In addition, two individuals presenting with more severe learning disabilities carried a 1.42 Mb 2p14 microdeletion, with three genes (CEP68, RAB1A and ACTR2),which are candidates for the intellectual impairment observed in the previously described 2p14p15 microdeletion syndrome, mapping to the minimal overlapping deleted segment. A 5p15.1 deletion, encompassing 1.47 Mb, also detected in the family, did not segregate with the clinical phenotype. Conclusion The disclosing of the complexity of an apparently simple two-break familial rearrangement illustrates the importance of reconstructing the precise structure of derivative chromosomes for establishing genotype-phenotype correlations. Electronic supplementary material The online version of this article (doi:10.1186/s13039-015-0205-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ana Carolina S Fonseca
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, Rua do Matão, 277, 05508-090 São Paulo, SP Brazil ; Wilhelm Johannsen Centre for Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Adriano Bonaldi
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, Rua do Matão, 277, 05508-090 São Paulo, SP Brazil
| | - Simone A S Fonseca
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, Rua do Matão, 277, 05508-090 São Paulo, SP Brazil
| | - Paulo A Otto
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, Rua do Matão, 277, 05508-090 São Paulo, SP Brazil
| | - Fernando Kok
- Department of Neurology, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil
| | - Mads Bak
- Wilhelm Johannsen Centre for Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Niels Tommerup
- Wilhelm Johannsen Centre for Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Angela M Vianna-Morgante
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, Rua do Matão, 277, 05508-090 São Paulo, SP Brazil
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24
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Dailey L. High throughput technologies for the functional discovery of mammalian enhancers: new approaches for understanding transcriptional regulatory network dynamics. Genomics 2015; 106:151-158. [PMID: 26072436 DOI: 10.1016/j.ygeno.2015.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Revised: 04/18/2015] [Accepted: 06/08/2015] [Indexed: 01/08/2023]
Abstract
Completion of the human and mouse genomes has inspired new initiatives to obtain a global understanding of the functional regulatory networks governing gene expression. Enhancers are primary regulatory DNA elements determining precise spatio- and temporal gene expression patterns, but the observation that they can function at any distance from the gene(s) they regulate has made their genome-wide characterization challenging. Since traditional, single reporter approaches would be unable to accomplish this enormous task, high throughput technologies for mapping chromatin features associated with enhancers have emerged as an effective surrogate for enhancer discovery. However, the last few years have witnessed the development of several new innovative approaches that can effectively screen for and discover enhancers based on their functional activation of transcription using massively parallel reporter systems. In addition to their application for genome annotation, these new high throughput functional approaches open new and exciting avenues for modeling gene regulatory networks.
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Affiliation(s)
- Lisa Dailey
- NYU School of Medicine, Department of Microbiology, Kimmel Center for Stem Cell Biology, 550 First Avenue, MSB 252, New York, NY 10016, United States.
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25
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Giorgio E, Robyr D, Spielmann M, Ferrero E, Di Gregorio E, Imperiale D, Vaula G, Stamoulis G, Santoni F, Atzori C, Gasparini L, Ferrera D, Canale C, Guipponi M, Pennacchio LA, Antonarakis SE, Brussino A, Brusco A. A large genomic deletion leads to enhancer adoption by the lamin B1 gene: a second path to autosomal dominant adult-onset demyelinating leukodystrophy (ADLD). Hum Mol Genet 2015; 24:3143-54. [PMID: 25701871 PMCID: PMC4424952 DOI: 10.1093/hmg/ddv065] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 02/13/2015] [Indexed: 01/23/2023] Open
Abstract
Chromosomal rearrangements with duplication of the lamin B1 (LMNB1) gene underlie autosomal dominant adult-onset demyelinating leukodystrophy (ADLD), a rare neurological disorder in which overexpression of LMNB1 causes progressive central nervous system demyelination. However, we previously reported an ADLD family (ADLD-1-TO) without evidence of duplication or other mutation in LMNB1 despite linkage to the LMNB1 locus and lamin B1 overexpression. By custom array-CGH, we further investigated this family and report here that patients carry a large (∼660 kb) heterozygous deletion that begins 66 kb upstream of the LMNB1 promoter. Lamin B1 overexpression was confirmed in further ADLD-1-TO tissues and in a postmortem brain sample, where lamin B1 was increased in the frontal lobe. Through parallel studies, we investigated both loss of genetic material and chromosomal rearrangement as possible causes of LMNB1 overexpression, and found that ADLD-1-TO plausibly results from an enhancer adoption mechanism. The deletion eliminates a genome topological domain boundary, allowing normally forbidden interactions between at least three forebrain-directed enhancers and the LMNB1 promoter, in line with the observed mainly cerebral localization of lamin B1 overexpression and myelin degeneration. This second route to LMNB1 overexpression and ADLD is a new example of the relevance of regulatory landscape modifications in determining Mendelian phenotypes.
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Affiliation(s)
- Elisa Giorgio
- Department of Medical Sciences, University of Torino, via Santena, 19, Torino 10126, Italy
| | - Daniel Robyr
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
| | - Malte Spielmann
- Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, Berlin 14195, Germany
| | - Enza Ferrero
- Department of Medical Sciences, University of Torino, via Santena, 19, Torino 10126, Italy
| | - Eleonora Di Gregorio
- Department of Medical Sciences, University of Torino, via Santena, 19, Torino 10126, Italy Medical Genetics Unit and
| | - Daniele Imperiale
- Centro Regionale Malattie Da Prioni - Domp (ASLTO2), Torino 10144, Italy
| | - Giovanna Vaula
- Department of Neurology, Città della Salute e della Scienza University Hospital, Torino 10126, Italy
| | - Georgios Stamoulis
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
| | - Federico Santoni
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
| | - Cristiana Atzori
- Centro Regionale Malattie Da Prioni - Domp (ASLTO2), Torino 10144, Italy
| | | | | | - Claudio Canale
- Department of Nanophysics, Istituto Italiano di Tecnologia, Genoa 16163, Italy and
| | - Michel Guipponi
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
| | - Len A Pennacchio
- Genomics Division, Lawrence Berkeley National Laboratory, MS 84-171, Berkeley, CA 9472, USA
| | - Stylianos E Antonarakis
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
| | - Alessandro Brussino
- Department of Medical Sciences, University of Torino, via Santena, 19, Torino 10126, Italy
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, via Santena, 19, Torino 10126, Italy Medical Genetics Unit and
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Kjeldsen E. A novel acquired cryptic three-way translocation t(2;11;5)(p21.3;q13.5;q23.2) with a submicroscopic deletion at 11p14.3 in an adult with hypereosinophilic syndrome. Exp Mol Pathol 2015; 99:50-5. [PMID: 25962659 DOI: 10.1016/j.yexmp.2015.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 05/01/2015] [Indexed: 11/19/2022]
Abstract
Hypereosinophilic syndrome (HES) is a clinically and pathologically heterogeneous disease entity. It is characterized by persistent eosinophilia and organ damage after excluding other causes. Clonal eosinophilia is distinguished from idiopathic eosinophilia by the presence of histologic, cytogenetic, or molecular evidence of an underlying malignancy. There are two distinct subcategories of clonal eosinophilia: chronic eosinophilic leukemia, not otherwise specified and myeloid/lymphoid neoplasms with eosinophilia and mutations involving platelet-derived growth factor receptor α/β or fibroblast growth factor receptor 1. More than 50% of HES are without knowledge of underlying pathogenic molecular pathways. Here we examined a HES patient by oligo-based aCGH analysis and molecular cytogenetic methods. Examination for the common eosinophilia-related cytogenetic abnormalities involving the genes PDGFRA, PDGFRB, and FGFR1 together with BCR-ABL fusion gene was negative. Cytogenetic analysis and multi-color FISH analysis revealed a novel cryptic three-way translocation t(2;11;5)(p21.3;q13.5;q23.2). By oaCGH analysis we could not find any copy number changes related to the cytogenetic breakpoints but instead detected a 0.9Mb submicroscopic deletion at 11p14.3. The deleted region involved the 5'-upstream sequences and exons 1-4 of the LUZP2 gene, which encodes a leucine zipper protein. Analysis of surrogate germ-line cells revealed a normal result showing that the detected chromosomal aberrations were acquired. This is the first report on a HES patient associated with a novel complex three-way translocation t(2;11;5)(p21.3;q13.5;q23.2) and a submicroscopic deletion in chromosome band 11p14.3. The study also demonstrates the benefits of oligo-based aCGH analysis in detecting hidden disease related chromosomal abnormalities. The present findings provide additional clues to unravel important molecular pathways in HES to obtain the full spectrum of acquired chromosomal and genomic aberrations in this heterogeneous disease entity. As more cases become characterized this may eventually improve on classification and treatment options.
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MESH Headings
- Aged
- Chromosome Deletion
- Chromosomes, Human, Pair 11/genetics
- Chromosomes, Human, Pair 2/genetics
- Chromosomes, Human, Pair 5/genetics
- Comparative Genomic Hybridization
- DNA-Binding Proteins/genetics
- Female
- Follow-Up Studies
- Humans
- Hypereosinophilic Syndrome/diagnosis
- Hypereosinophilic Syndrome/genetics
- In Situ Hybridization, Fluorescence
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Platelet-Derived Growth Factor alpha/genetics
- Receptor, Platelet-Derived Growth Factor beta/genetics
- Translocation, Genetic
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Affiliation(s)
- Eigil Kjeldsen
- HemoDiagnostic Laboratory, CancerCytogenetic Section, Department of Hematology, Aarhus University Hospital, Tage-Hansens Gade 2, Ent. 4A, DK-8000 Aarhus C, Denmark.
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Pazin MJ. Using the ENCODE Resource for Functional Annotation of Genetic Variants. Cold Spring Harb Protoc 2015; 2015:522-36. [PMID: 25762420 DOI: 10.1101/pdb.top084988] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This article illustrates the use of the Encyclopedia of DNA Elements (ENCODE) resource to generate or refine hypotheses from genomic data on disease and other phenotypic traits. First, the goals and history of ENCODE and related epigenomics projects are reviewed. Second, the rationale for ENCODE and the major data types used by ENCODE are briefly described, as are some standard heuristics for their interpretation. Third, the use of the ENCODE resource is examined. Standard use cases for ENCODE, accessing the ENCODE resource, and accessing data from related projects are discussed. Although the focus of this article is the use of ENCODE data, some of the same approaches can be used with data from other projects.
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Affiliation(s)
- Michael J Pazin
- Division of Genome Sciences, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892
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28
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Thomas LE, Winston J, Rad E, Mort M, Dodd KM, Tee AR, McDyer F, Moore S, Cooper DN, Upadhyaya M. Evaluation of copy number variation and gene expression in neurofibromatosis type-1-associated malignant peripheral nerve sheath tumours. Hum Genomics 2015; 9:3. [PMID: 25884485 PMCID: PMC4367978 DOI: 10.1186/s40246-015-0025-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 01/18/2015] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Neurofibromatosis type-1 (NF1) is a complex neurogenetic disorder characterised by the development of benign and malignant tumours of the peripheral nerve sheath (MPNSTs). Whilst biallelic NF1 gene inactivation contributes to benign tumour formation, additional cellular changes in gene structure and/or expression are required to induce malignant transformation. Although few molecular profiling studies have been performed on the process of progression of pre-existing plexiform neurofibromas to MPNSTs, the integrated analysis of copy number alterations (CNAs) and gene expression is likely to be key to understanding the molecular mechanisms underlying NF1-MPNST tumorigenesis. In a pilot study, we employed this approach to identify genes differentially expressed between benign and malignant NF1 tumours. RESULTS SPP1 (osteopontin) was the most differentially expressed gene (85-fold increase in expression), compared to benign plexiform neurofibromas. Short hairpin RNA (shRNA) knockdown of SPP1 in NF1-MPNST cells reduced tumour spheroid size, wound healing and invasion in four different MPNST cell lines. Seventy-six genes were found to exhibit concordance between CNA and gene expression level. CONCLUSIONS Pathway analysis of these genes suggested that glutathione metabolism and Wnt signalling may be specifically involved in NF1-MPNST development. SPP1 is associated with malignant transformation in NF1-associated MPNSTs and could prove to be an important target for therapeutic intervention.
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Affiliation(s)
- Laura E Thomas
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
| | - Jincy Winston
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
| | - Ellie Rad
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
| | - Matthew Mort
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
| | - Kayleigh M Dodd
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
| | - Andrew R Tee
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
| | - Fionnuala McDyer
- Almac Diagnostics, 19 Seagoe Industrial Estate, Craigavon, Northern Ireland, BT63 5QD, UK.
| | - Stephen Moore
- Almac Diagnostics, 19 Seagoe Industrial Estate, Craigavon, Northern Ireland, BT63 5QD, UK.
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
| | - Meena Upadhyaya
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
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29
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Wang J, Lawry ST, Cohen AL, Jia S. Chromosome boundary elements and regulation of heterochromatin spreading. Cell Mol Life Sci 2014; 71:4841-52. [PMID: 25192661 PMCID: PMC4234687 DOI: 10.1007/s00018-014-1725-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 08/27/2014] [Accepted: 08/29/2014] [Indexed: 11/29/2022]
Abstract
Chromatin is generally classified as euchromatin or heterochromatin, each with distinct histone modifications, compaction levels, and gene expression patterns. Although the proper formation of heterochromatin is essential for maintaining genome integrity and regulating gene expression, heterochromatin can also spread into neighboring regions in a sequence-independent manner, leading to the inactivation of genes. Because the distance of heterochromatin spreading is stochastic, the formation of boundaries, which block the spreading of heterochromatin, is critical for maintaining stable gene expression patterns. Here we review the current understanding of the mechanisms underlying heterochromatin spreading and boundary formation.
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Affiliation(s)
- Jiyong Wang
- Department of Biological Sciences, Columbia University, New York, NY, USA
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30
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Morange M. What history tells us XXXV. Enhancers: their existence and characteristics have raised puzzling issues since their discovery. J Biosci 2014; 39:741-5. [PMID: 25431403 DOI: 10.1007/s12038-014-9482-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michel Morange
- Centre Cavailles, Republique des Savoirs USR 3608, Ecole Normale Superieure, 29 rue d'Ulm, 75230 Paris Cedex 05, France,
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31
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Racca JD, Chen YS, Maloy JD, Wickramasinghe N, Phillips NB, Weiss MA. Structure-function relationships in human testis-determining factor SRY: an aromatic buttress underlies the specific DNA-bending surface of a high mobility group (HMG) box. J Biol Chem 2014; 289:32410-29. [PMID: 25258310 DOI: 10.1074/jbc.m114.597526] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human testis determination is initiated by SRY, a Y-encoded architectural transcription factor. Mutations in SRY cause 46 XY gonadal dysgenesis with female somatic phenotype (Swyer syndrome) and confer a high risk of malignancy (gonadoblastoma). Such mutations cluster in the SRY high mobility group (HMG) box, a conserved motif of specific DNA binding and bending. To explore structure-function relationships, we constructed all possible substitutions at a site of clinical mutation (W70L). Our studies thus focused on a core aromatic residue (position 15 of the consensus HMG box) that is invariant among SRY-related HMG box transcription factors (the SOX family) and conserved as aromatic (Phe or Tyr) among other sequence-specific boxes. In a yeast one-hybrid system sensitive to specific SRY-DNA binding, the variant domains exhibited reduced (Phe and Tyr) or absent activity (the remaining 17 substitutions). Representative nonpolar variants with partial or absent activity (Tyr, Phe, Leu, and Ala in order of decreasing side-chain volume) were chosen for study in vitro and in mammalian cell culture. The clinical mutation (Leu) was found to markedly impair multiple biochemical and cellular activities as respectively probed through the following: (i) in vitro assays of specific DNA binding and protein stability, and (ii) cell culture-based assays of proteosomal degradation, nuclear import, enhancer DNA occupancy, and SRY-dependent transcriptional activation. Surprisingly, however, DNA bending is robust to this or the related Ala substitution that profoundly impairs box stability. Together, our findings demonstrate that the folding, trafficking, and gene-regulatory function of SRY requires an invariant aromatic "buttress" beneath its specific DNA-bending surface.
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Affiliation(s)
- Joseph D Racca
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Yen-Shan Chen
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - James D Maloy
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Nalinda Wickramasinghe
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Nelson B Phillips
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Michael A Weiss
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
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32
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A high resolution map of mammalian X chromosome fragile regions assessed by large-scale comparative genomics. Mamm Genome 2014; 25:618-35. [PMID: 25086724 DOI: 10.1007/s00335-014-9537-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 07/14/2014] [Indexed: 10/24/2022]
Abstract
Chromosomal evolution involves multiple changes at structural and numerical levels. These changes, which are related to the variation of the gene number and their location, can be tracked by the identification of syntenic blocks (SB). First reports proposed that ~180-280 SB might be shared by mouse and human species. More recently, further studies including additional genomes have identified up to ~1,400 SB during the evolution of eutherian species. A considerable number of studies regarding the X chromosome's structure and evolution have been undertaken because of its extraordinary biological impact on reproductive fitness and speciation. Some have identified evolutionary breakpoint regions and fragile sites at specific locations in the human X chromosome. However, mapping these regions to date has involved using low-to-moderate resolution techniques. Such scenario might be related to underestimating their total number and giving an inaccurate location. The present study included using a combination of bioinformatics methods for identifying, at base-pair level, chromosomal rearrangements occurring during X chromosome evolution in 13 mammalian species. A comparative technique using four different algorithms was used for optimizing the detection of hotspot regions in the human X chromosome. We identified a significant interspecific variation in SB size which was related to genetic information gain regarding the human X chromosome. We found that human hotspot regions were enriched by LINE-1 and Alu transposable elements, which may have led to intraspecific chromosome rearrangement events. New fragile regions located in the human X chromosome have also been postulated. We estimate that the high resolution map of X chromosome fragile sites presented here constitutes useful data concerning future studies on mammalian evolution and human disease.
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33
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Dickel DE, Zhu Y, Nord AS, Wylie JN, Akiyama JA, Afzal V, Plajzer-Frick I, Kirkpatrick A, Göttgens B, Bruneau BG, Visel A, Pennacchio LA. Function-based identification of mammalian enhancers using site-specific integration. Nat Methods 2014; 11:566-71. [PMID: 24658141 PMCID: PMC4008384 DOI: 10.1038/nmeth.2886] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/03/2014] [Indexed: 01/22/2023]
Abstract
The accurate and comprehensive identification of functional regulatory sequences in mammalian genomes remains a major challenge. Here we describe site-specific integration fluorescence-activated cell sorting followed by sequencing (SIF-seq), an unbiased, medium-throughput functional assay for the discovery of distant-acting enhancers. Targeted single-copy genomic integration into pluripotent cells, reporter assays and flow cytometry are coupled with high-throughput DNA sequencing to enable parallel screening of large numbers of DNA sequences. By functionally interrogating >500 kilobases (kb) of mouse and human sequence in mouse embryonic stem cells for enhancer activity we identified enhancers at pluripotency loci including NANOG. In in vitro-differentiated cardiomyocytes and neural progenitor cells, we identified cardiac enhancers and neuronal enhancers, respectively. SIF-seq is a powerful and flexible method for de novo functional identification of mammalian enhancers in a potentially wide variety of cell types.
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Affiliation(s)
- Diane E Dickel
- Genomics Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Yiwen Zhu
- Genomics Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Alex S Nord
- Genomics Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - John N Wylie
- 1] Gladstone Institute of Cardiovascular Disease, San Francisco, California, USA. [2] Roddenberry Center for Stem Cell Biology and Medicine at Gladstone Institutes, San Francisco, California, USA
| | - Jennifer A Akiyama
- Genomics Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Veena Afzal
- Genomics Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Ingrid Plajzer-Frick
- Genomics Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Aileen Kirkpatrick
- 1] Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK. [2] Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Berthold Göttgens
- 1] Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK. [2] Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Benoit G Bruneau
- 1] Gladstone Institute of Cardiovascular Disease, San Francisco, California, USA. [2] Roddenberry Center for Stem Cell Biology and Medicine at Gladstone Institutes, San Francisco, California, USA. [3] Department of Pediatrics, University of California, San Francisco, San Francisco, California, USA. [4] Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California, USA
| | - Axel Visel
- 1] Genomics Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA. [2] US Department of Energy Joint Genome Institute, Walnut Creek, California, USA. [3] School of Natural Sciences, University of California, Merced, Merced, California, USA
| | - Len A Pennacchio
- 1] Genomics Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA. [2] US Department of Energy Joint Genome Institute, Walnut Creek, California, USA
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34
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Abstract
With the completion of the human genome sequence, attention turned to identifying and annotating its functional DNA elements. As a complement to genetic and comparative genomics approaches, the Encyclopedia of DNA Elements Project was launched to contribute maps of RNA transcripts, transcriptional regulator binding sites, and chromatin states in many cell types. The resulting genome-wide data reveal sites of biochemical activity with high positional resolution and cell type specificity that facilitate studies of gene regulation and interpretation of noncoding variants associated with human disease. However, the biochemically active regions cover a much larger fraction of the genome than do evolutionarily conserved regions, raising the question of whether nonconserved but biochemically active regions are truly functional. Here, we review the strengths and limitations of biochemical, evolutionary, and genetic approaches for defining functional DNA segments, potential sources for the observed differences in estimated genomic coverage, and the biological implications of these discrepancies. We also analyze the relationship between signal intensity, genomic coverage, and evolutionary conservation. Our results reinforce the principle that each approach provides complementary information and that we need to use combinations of all three to elucidate genome function in human biology and disease.
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35
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Targeting of Slc25a21 is associated with orofacial defects and otitis media due to disrupted expression of a neighbouring gene. PLoS One 2014; 9:e91807. [PMID: 24642684 PMCID: PMC3958370 DOI: 10.1371/journal.pone.0091807] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 02/13/2014] [Indexed: 12/24/2022] Open
Abstract
Homozygosity for Slc25a21tm1a(KOMP)Wtsi results in mice exhibiting orofacial abnormalities, alterations in carpal and rugae structures, hearing impairment and inflammation in the middle ear. In humans it has been hypothesised that the 2-oxoadipate mitochondrial carrier coded by SLC25A21 may be involved in the disease 2-oxoadipate acidaemia. Unexpectedly, no 2-oxoadipate acidaemia-like symptoms were observed in animals homozygous for Slc25a21tm1a(KOMP)Wtsi despite confirmation that this allele reduces Slc25a21 expression by 71.3%. To study the complete knockout, an allelic series was generated using the loxP and FRT sites typical of a Knockout Mouse Project allele. After removal of the critical exon and neomycin selection cassette, Slc25a21 knockout mice homozygous for the Slc25a21tm1b(KOMP)Wtsi and Slc25a21tm1d(KOMP)Wtsi alleles were phenotypically indistinguishable from wild-type. This led us to explore the genomic environment of Slc25a21 and to discover that expression of Pax9, located 3′ of the target gene, was reduced in homozygous Slc25a21tm1a(KOMP)Wtsi mice. We hypothesize that the presence of the selection cassette is the cause of the down regulation of Pax9 observed. The phenotypes we observed in homozygous Slc25a21tm1a(KOMP)Wtsi mice were broadly consistent with a hypomorphic Pax9 allele with the exception of otitis media and hearing impairment which may be a novel consequence of Pax9 down regulation. We explore the ramifications associated with this particular targeted mutation and emphasise the need to interpret phenotypes taking into consideration all potential underlying genetic mechanisms.
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36
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McHugh KM. Megabladder mouse model of congenital obstructive nephropathy: genetic etiology and renal adaptation. Pediatr Nephrol 2014; 29:645-50. [PMID: 24276861 PMCID: PMC3928515 DOI: 10.1007/s00467-013-2658-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 10/03/2013] [Accepted: 10/04/2013] [Indexed: 01/23/2023]
Abstract
Congenital obstructive nephropathy remains one of the leading causes of chronic renal failure in children. The direct link between obstructed urine flow and abnormal renal development and subsequent dysfunction represents a central paradigm of urogenital pathogenesis that has far-reaching clinical implications. Even so, a number of diagnostic, prognostic, and therapeutic quandaries still exist in the management of congenital obstructive nephropathy. Studies in our laboratory have characterized a unique mutant mouse line that develops in utero megabladder, variable hydronephrosis, and progressive renal failure. Megabladder mice represent a valuable functional model for the study of congenital obstructive nephropathy. Recent studies have begun to shed light on the genetic etiology of mgb (-/-) mice as well as the molecular pathways controlling disease progression in these animals.
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Affiliation(s)
- Kirk M. McHugh
- Department of Pediatrics and Division of Anatomy, College of Medicine, The Ohio State University, Columbus, OH 43210 USA ,Center for Molecular and Human Genetics, The Research Institute, Nationwide Children’s Hospital, Columbus, OH 43205 USA
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37
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Structural variation-associated expression changes are paralleled by chromatin architecture modifications. PLoS One 2013; 8:e79973. [PMID: 24265791 PMCID: PMC3827143 DOI: 10.1371/journal.pone.0079973] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 10/07/2013] [Indexed: 01/04/2023] Open
Abstract
Copy number variants (CNVs) influence the expression of genes that map not only within the rearrangement, but also to its flanks. To assess the possible mechanism(s) underlying this “neighboring effect”, we compared intrachromosomal interactions and histone modifications in cell lines of patients affected by genomic disorders and control individuals. Using chromosome conformation capture (4C-seq), we observed that a set of genes flanking the Williams-Beuren Syndrome critical region (WBSCR) were often looping together. The newly identified interacting genes include AUTS2, mutations of which are associated with autism and intellectual disabilities. Deletion of the WBSCR disrupts the expression of this group of flanking genes, as well as long-range interactions between them and the rearranged interval. We also pinpointed concomitant changes in histone modifications between samples. We conclude that large genomic rearrangements can lead to chromatin conformation changes that extend far away from the structural variant, thereby possibly modulating expression globally and modifying the phenotype. GEO Series accession number: GSE33784, GSE33867.
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38
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Hiller M, Agarwal S, Notwell JH, Parikh R, Guturu H, Wenger AM, Bejerano G. Computational methods to detect conserved non-genic elements in phylogenetically isolated genomes: application to zebrafish. Nucleic Acids Res 2013; 41:e151. [PMID: 23814184 PMCID: PMC3753653 DOI: 10.1093/nar/gkt557] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Many important model organisms for biomedical and evolutionary research have sequenced genomes, but occupy a phylogenetically isolated position, evolutionarily distant from other sequenced genomes. This phylogenetic isolation is exemplified for zebrafish, a vertebrate model for cis-regulation, development and human disease, whose evolutionary distance to all other currently sequenced fish exceeds the distance between human and chicken. Such large distances make it difficult to align genomes and use them for comparative analysis beyond gene-focused questions. In particular, detecting conserved non-genic elements (CNEs) as promising cis-regulatory elements with biological importance is challenging. Here, we develop a general comparative genomics framework to align isolated genomes and to comprehensively detect CNEs. Our approach integrates highly sensitive and quality-controlled local alignments and uses alignment transitivity and ancestral reconstruction to bridge large evolutionary distances. We apply our framework to zebrafish and demonstrate substantially improved CNE detection and quality compared with previous sets. Our zebrafish CNE set comprises 54 533 CNEs, of which 11 792 (22%) are conserved to human or mouse. Our zebrafish CNEs (http://zebrafish.stanford.edu) are highly enriched in known enhancers and extend existing experimental (ChIP-Seq) sets. The same framework can now be applied to the isolated genomes of frog, amphioxus, Caenorhabditis elegans and many others.
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Affiliation(s)
- Michael Hiller
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA, Department of Computer Science, Stanford University, Stanford, CA 94305, USA and Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
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39
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Pennacchio LA, Bickmore W, Dean A, Nobrega MA, Bejerano G. Enhancers: five essential questions. Nat Rev Genet 2013; 14:288-95. [PMID: 23503198 DOI: 10.1038/nrg3458] [Citation(s) in RCA: 352] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
It is estimated that the human genome contains hundreds of thousands of enhancers, so understanding these gene-regulatory elements is a crucial goal. Several fundamental questions need to be addressed about enhancers, such as how do we identify them all, how do they work, and how do they contribute to disease and evolution? Five prominent researchers in this field look at how much we know already and what needs to be done to answer these questions.
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Affiliation(s)
- Len A Pennacchio
- Genomics Division, One Cyclotron Road, MS 84-171, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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40
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Dickel DE, Visel A, Pennacchio LA. Functional anatomy of distant-acting mammalian enhancers. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120359. [PMID: 23650633 DOI: 10.1098/rstb.2012.0359] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Transcriptional enhancers are a major class of functional element embedded in the vast non-coding portion of the human genome. Acting over large genomic distances, enhancers play critical roles in the tissue and cell type-specific regulation of genes, and there is mounting evidence that they contribute to the aetiology of many human diseases. Methods for genome-wide mapping of enhancer regions are now available, but the functional architecture contained within human enhancer elements remains unclear. Here, we review recent approaches aimed at understanding the functional anatomy of individual enhancer elements, using systematic qualitative and quantitative assessments of mammalian enhancer variants in cultured cells and in vivo. These studies provide direct insight into common architectural characteristics of enhancers including the presence of multiple transcription factor-binding sites and the mixture of both transcriptionally activating and repressing domains within the same enhancer. Despite such progress in understanding the functional composition of enhancers, the inherent complexities of enhancer anatomy continue to limit our ability to predict the impact of sequence changes on in vivo enhancer function. While providing an initial glimpse into the mutability of mammalian enhancers, these observations highlight the continued need for experimental enhancer assessment as genome sequencing becomes routine in the clinic.
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Affiliation(s)
- D E Dickel
- Genomics Division, MS 84-171, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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41
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Betts JA, French JD, Brown MA, Edwards SL. Long-range transcriptional regulation of breast cancer genes. Genes Chromosomes Cancer 2012; 52:113-25. [PMID: 23077082 DOI: 10.1002/gcc.22020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 09/19/2012] [Accepted: 09/19/2012] [Indexed: 12/11/2022] Open
Abstract
Breast cancer is a major health problem and understanding the genetic basis of this disease is crucial for predicting risk and developing effective targeted therapeutics. Several breast cancer predisposing genes have been identified, but mutations in the coding regions of these genes only accounts for a small proportion of risk. Research now suggests that combinations of multiple non-coding changes in breast cancer susceptibility genes, which cause moderate alterations in gene expression, will be responsible for the remaining inherited risk. These non-coding changes will include variants in proximal and distal transcriptional and post-transcriptional regulatory elements and may affect the levels and function of trans-acting factors, including proteins and RNAs, which act on these elements. Somatic changes in such elements and factors have also been associated with breast cancer progression. With the recent advent of techniques allowing the detection of long-range DNA interactions spanning the human genome, it has become increasingly clear that long-range regulatory elements constitute an important mechanism for gene regulation. Recent studies have identified several such elements that are important for regulating genes involved in breast cancer, raising the possibility that defects in these sequences may contribute to breast cancer predisposition and progression. In this review, we discuss the emerging functions of cis-regulatory elements and a subset of trans-acting factors in breast tumorigenesis. We also discuss some recent progress in our understanding of how dysregulation in these transcriptional components may contribute to breast cancer, and the potential implications for molecular diagnosis, prognosis prediction, and the treatment of this disease.
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Affiliation(s)
- Joshua A Betts
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
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42
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Palstra RJ, Grosveld F. Transcription factor binding at enhancers: shaping a genomic regulatory landscape in flux. Front Genet 2012; 3:195. [PMID: 23060900 PMCID: PMC3460357 DOI: 10.3389/fgene.2012.00195] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 09/12/2012] [Indexed: 12/26/2022] Open
Abstract
The mammalian genome is packed tightly in the nucleus of the cell. This packing is primarily facilitated by histone proteins and results in an ordered organization of the genome in chromosome territories that can be roughly divided in heterochromatic and euchromatic domains. On top of this organization several distinct gene regulatory elements on the same chromosome or other chromosomes are thought to dynamically communicate via chromatin looping. Advances in genome-wide technologies have revealed the existence of a plethora of these regulatory elements in various eukaryotic genomes. These regulatory elements are defined by particular in vitro assays as promoters, enhancers, insulators, and boundary elements. However, recent studies indicate that the in vivo distinction between these elements is often less strict. Regulatory elements are bound by a mixture of common and lineage-specific transcription factors which mediate the long-range interactions between these elements. Inappropriate modulation of the binding of these transcription factors can alter the interactions between regulatory elements, which in turn leads to aberrant gene expression with disease as an ultimate consequence. Here we discuss the bi-modal behavior of regulatory elements that act in cis (with a focus on enhancers), how their activity is modulated by transcription factor binding and the effect this has on gene regulation.
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Affiliation(s)
- Robert-Jan Palstra
- Department of Cell Biology, Erasmus MC University Medical Center Rotterdam, Netherlands
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43
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Naidoo N, Pawitan Y, Soong R, Cooper DN, Ku CS. Human genetics and genomics a decade after the release of the draft sequence of the human genome. Hum Genomics 2012; 5:577-622. [PMID: 22155605 PMCID: PMC3525251 DOI: 10.1186/1479-7364-5-6-577] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Substantial progress has been made in human genetics and genomics research over the past ten years since the publication of the draft sequence of the human genome in 2001. Findings emanating directly from the Human Genome Project, together with those from follow-on studies, have had an enormous impact on our understanding of the architecture and function of the human genome. Major developments have been made in cataloguing genetic variation, the International HapMap Project, and with respect to advances in genotyping technologies. These developments are vital for the emergence of genome-wide association studies in the investigation of complex diseases and traits. In parallel, the advent of high-throughput sequencing technologies has ushered in the 'personal genome sequencing' era for both normal and cancer genomes, and made possible large-scale genome sequencing studies such as the 1000 Genomes Project and the International Cancer Genome Consortium. The high-throughput sequencing and sequence-capture technologies are also providing new opportunities to study Mendelian disorders through exome sequencing and whole-genome sequencing. This paper reviews these major developments in human genetics and genomics over the past decade.
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Affiliation(s)
- Nasheen Naidoo
- Centre for Molecular Epidemiology, Department of Epidemiology and Public Health, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Nora EP, Lajoie BR, Schulz EG, Giorgetti L, Okamoto I, Servant N, Piolot T, van Berkum NL, Meisig J, Sedat J, Gribnau J, Barillot E, Blüthgen N, Dekker J, Heard E. Spatial partitioning of the regulatory landscape of the X-inactivation centre. Nature 2012; 485:381-5. [PMID: 22495304 DOI: 10.1038/nature11049] [Citation(s) in RCA: 2012] [Impact Index Per Article: 167.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 03/22/2012] [Indexed: 12/21/2022]
Abstract
In eukaryotes transcriptional regulation often involves multiple long-range elements and is influenced by the genomic environment. A prime example of this concerns the mouse X-inactivation centre (Xic), which orchestrates the initiation of X-chromosome inactivation (XCI) by controlling the expression of the non-protein-coding Xist transcript. The extent of Xic sequences required for the proper regulation of Xist remains unknown. Here we use chromosome conformation capture carbon-copy (5C) and super-resolution microscopy to analyse the spatial organization of a 4.5-megabases (Mb) region including Xist. We discover a series of discrete 200-kilobase to 1 Mb topologically associating domains (TADs), present both before and after cell differentiation and on the active and inactive X. TADs align with, but do not rely on, several domain-wide features of the epigenome, such as H3K27me3 or H3K9me2 blocks and lamina-associated domains. TADs also align with coordinately regulated gene clusters. Disruption of a TAD boundary causes ectopic chromosomal contacts and long-range transcriptional misregulation. The Xist/Tsix sense/antisense unit illustrates how TADs enable the spatial segregation of oppositely regulated chromosomal neighbourhoods, with the respective promoters of Xist and Tsix lying in adjacent TADs, each containing their known positive regulators. We identify a novel distal regulatory region of Tsix within its TAD, which produces a long intervening RNA, Linx. In addition to uncovering a new principle of cis-regulatory architecture of mammalian chromosomes, our study sets the stage for the full genetic dissection of the X-inactivation centre.
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Tschopp P, Duboule D. A genetic approach to the transcriptional regulation of Hox gene clusters. Annu Rev Genet 2012; 45:145-66. [PMID: 22060042 DOI: 10.1146/annurev-genet-102209-163429] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The evolution of vertebrate genomes was accompanied by an astounding increase in the complexity of their regulatory modalities. Genetic redundancy resulting from large-scale genome duplications at the base of the chordate tree was repeatedly exploited by the functional redeployment of paralogous genes via innovations in their regulatory circuits. As a paradigm of such regulatory evolution, we have extensively studied those control mechanisms at work in-cis over vertebrate Hox gene clusters. Here, we review the portfolio of genetic strategies that have been developed to tackle the intricate relationship between genomic topography and the transcriptional activities in this gene family, and we describe some of the mechanistic insights we gained by using the HoxD cluster as an example. We discuss the high heuristic value of this system in our general understanding of how changes in transcriptional regulation can diversify gene function and thereby fuel morphological evolution.
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Affiliation(s)
- Patrick Tschopp
- National Center of Competence in Research, Frontiers in Genetics, Department of Genetics and Evolution, University of Geneva, 1211 Geneva 4, Switzerland
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Benko S, Gordon CT, Amiel J, Lyonnet S. [Cis-ruptions of highly conserved non-coding genomic elements distant from the SOX9 gene in the Pierre Robin sequence]. Biol Aujourdhui 2011; 205:111-124. [PMID: 21831342 DOI: 10.1051/jbio/2011010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Indexed: 05/31/2023]
Abstract
Major developmental genes, exhibiting complex expression patterns, are often embedded within a genic desert particularly rich in regions, which though non-coding are highly conserved. The developmental expression of these genes in many areas requires coordinated regulation in time and space, which is orchestrated by some of these conserved non-coding regions, acting as transcriptional regulators. SOX9 is an essential gene for many developmental processes, such as chondrogenesis, migration and differentiation of neural crest cells and testis development. In agreement with these major expression areas, SOX9 haploinsufficiency, linked to alterations in coding sequence, leads to a polymorphic malformation syndrome - campomelic dysplasia - whose major symptoms are a bone anomaly, a Pierre Robin sequence, and a sexual differentiation anomaly (Disorder of Sex Development, DSD). SOX9 is located in a ~2.5 Mb gene desert extremely rich in conserved sequences. We have used the SOX9 locus and campomelic dysplasia as a model to show that one or several endophenotypes within a complex syndrome may arise from a tissue-specific deregulation of a major developmental gene transcription. Our work has focused on one of these endophenotypes, SPR, characterized by the triad micro- and/or retrognathy, glossoptosis and cleft palate. Here we report in detail how we identified alterations (translocations, deletions, point mutations) in non-coding regions, located far away (more than 1.2 Mb) upstream and downstream of SOX9, in clustered or sporadic SPR cases.
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Affiliation(s)
- Sabina Benko
- Département de génétique, Université Paris Descartes et Inserm U-781, Hôpital Necker-Enfants Malades, Paris Cedex, France
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Ma MKW, Heath C, Hair A, West AG. Histone crosstalk directed by H2B ubiquitination is required for chromatin boundary integrity. PLoS Genet 2011; 7:e1002175. [PMID: 21811414 PMCID: PMC3140996 DOI: 10.1371/journal.pgen.1002175] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 05/23/2011] [Indexed: 12/21/2022] Open
Abstract
Genomic maps of chromatin modifications have provided evidence for the partitioning of genomes into domains of distinct chromatin states, which assist coordinated gene regulation. The maintenance of chromatin domain integrity can require the setting of boundaries. The HS4 insulator element marks the 3′ boundary of a heterochromatin region located upstream of the chicken β-globin gene cluster. Here we show that HS4 recruits the E3 ligase RNF20/BRE1A to mediate H2B mono-ubiquitination (H2Bub1) at this insulator. Knockdown experiments show that RNF20 is required for H2Bub1 and processive H3K4 methylation. Depletion of RNF20 results in a collapse of the active histone modification signature at the HS4 chromatin boundary, where H2Bub1, H3K4 methylation, and hyperacetylation of H3, H4, and H2A.Z are rapidly lost. A remarkably similar set of events occurs at the HSA/HSB regulatory elements of the FOLR1 gene, which mark the 5′ boundary of the same heterochromatin region. We find that persistent H2Bub1 at the HSA/HSB and HS4 elements is required for chromatin boundary integrity. The loss of boundary function leads to the sequential spreading of H3K9me2, H3K9me3, and H4K20me3 over the entire 50 kb FOLR1 and β-globin region and silencing of FOLR1 expression. These findings show that the HSA/HSB and HS4 boundary elements direct a cascade of active histone modifications that defend the FOLR1 and β-globin gene loci from the pervasive encroachment of an adjacent heterochromatin domain. We propose that many gene loci employ H2Bub1-dependent boundaries to prevent heterochromatin spreading. The transcription of genes in eukaryotes occurs within the context of chromatin, a complex of DNA, histone proteins, and regulatory factors. Whole-genome profiling of chromatin proteins and histones that are post-translationally modified has revealed that genomes are organized into domains of distinct chromatin states that coordinate gene regulation. The integrity of chromatin domains can require the setting of their boundaries. DNA sequences known as chromatin insulator or boundary elements can establish boundaries between transcriptionally permissive and repressive chromatin domains. We have studied two chromatin boundary elements that flank a condensed chromatin region located between the chicken FOLR1 and β-globin genes, respectively. These elements recruit enzymes that mediate the ubiquitination of histone H2B. Histone H2B ubiquitination directs a cascade of so-called “active” histone modification events that favor chromatin accessibility. We observe a striking collapse of the active histone modification signature at both chromatin boundaries following the depletion of ubiquitinated H2B. This loss of boundary function leads to the comprehensive spreading of repressive chromatin over the entire FOLR1 and β-globin gene region, resulting in gene silencing. We propose that chromatin boundaries at many gene loci employ H2B ubiquitination to restrict the encroachment of repressive chromatin.
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Affiliation(s)
- Meiji Kit-Wan Ma
- Institute of Cancer Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Kortüm F, Das S, Flindt M, Morris-Rosendahl DJ, Stefanova I, Goldstein A, Horn D, Klopocki E, Kluger G, Martin P, Rauch A, Roumer A, Saitta S, Walsh LE, Wieczorek D, Uyanik G, Kutsche K, Dobyns WB. The core FOXG1 syndrome phenotype consists of postnatal microcephaly, severe mental retardation, absent language, dyskinesia, and corpus callosum hypogenesis. J Med Genet 2011; 48:396-406. [PMID: 21441262 DOI: 10.1136/jmg.2010.087528] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Submicroscopic deletions in 14q12 spanning FOXG1 or intragenic mutations have been reported in patients with a developmental disorder described as a congenital variant of Rett syndrome. This study aimed to further characterise and delineate the phenotype of FOXG1 mutation positive patients. METHOD The study mapped the breakpoints of a 2;14 translocation by fluorescence in situ hybridisation and analysed three chromosome rearrangements in 14q12 by cytogenetic analysis and/or array comparative genomic hybridisation. The FOXG1 gene was sequenced in 210 patients, including 129 patients with unexplained developmental disorders and 81 MECP2 mutation negative individuals. RESULTS One known mutation, seen in two patients, and nine novel mutations of FOXG1 including two deletions, two chromosome rearrangements disrupting or displacing putative cis-regulatory elements from FOXG1, and seven sequence changes, are reported. Analysis of 11 patients in this study, and a further 15 patients reported in the literature, demonstrates a complex constellation of features including mild postnatal growth deficiency, severe postnatal microcephaly, severe mental retardation with absent language development, deficient social reciprocity resembling autism, combined stereotypies and frank dyskinesias, epilepsy, poor sleep patterns, irritability in infancy, unexplained episodes of crying, recurrent aspiration, and gastro-oesophageal reflux. Brain imaging studies reveal simplified gyral pattern and reduced white matter volume in the frontal lobes, corpus callosum hypogenesis, and variable mild frontal pachgyria. CONCLUSIONS These findings have significantly expanded the number of FOXG1 mutations and identified two affecting possible cis-regulatory elements. While the phenotype of the patients overlaps both classic and congenital Rett syndrome, extensive clinical evaluation demonstrates a distinctive and clinically recognisable phenotype which the authors suggest designating as the FOXG1 syndrome.
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Affiliation(s)
- Fanny Kortüm
- Institut für Humangenetik, Universitätsklinikum Hamburg-Eppendorf, Campus Forschung, Martinistraße 52, 20246 Hamburg, Germany
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Abstract
The number of known mutations in human nuclear genes, underlying or associated with human inherited disease, has now exceeded 100,000 in more than 3700 different genes (Human Gene Mutation Database). However, for a variety of reasons, this figure is likely to represent only a small proportion of the clinically relevant genetic variants that remain to be identified in the human genome (the 'mutome'). With the advent of next-generation sequencing, we are currently witnessing a revolution in medical genetics. In particular, whole-genome sequencing (WGS) has the potential to identify all disease-causing or disease-associated DNA variants in a given individual. Here, we use examples of recent advances in our understanding of mutational/pathogenic mechanisms to guide our thinking about possible locations outwith gene-coding sequences for those disease-causing or disease-associated variants that are likely so often to have been overlooked because of the inadequacy of current mutation screening protocols. Such considerations are important not only for improving mutation-screening strategies but also for enhancing the interpretation of findings derived from genome-wide association studies, whole-exome sequencing and WGS. An improved understanding of the human mutome will not only lead to the development of improved diagnostic testing procedures but should also improve our understanding of human genome biology.
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Affiliation(s)
- J M Chen
- Etablissement Français du Sang (EFS) - Bretagne, Brest, France.
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Paar V, Gluncic M, Rosandic M, Basar I, Vlahovic I. Intragene Higher Order Repeats in Neuroblastoma BreakPoint Family Genes Distinguish Humans from Chimpanzees. Mol Biol Evol 2011; 28:1877-92. [DOI: 10.1093/molbev/msr009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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